Symposium Organizers
" " " Brookhaven National Laboratory
Mato Knez Max Planck Institute of Microstructure Physics
Stanislaus S. Wong State University of New York at Stony Brook
Hongjin Fan Nanyang Technological University
Woo Lee Korea Research Institute of Standards and Science (KRISS)
D1: Bioinspired Approaches
Session Chairs
Tuesday PM, November 29, 2011
Back Bay B (Sheraton)
9:30 AM - D1.1
Seed-Assisted Synthesis of Mordenite Zeolite by Using Indonesian Naturally-Occuring Minerals.
Rino Mukti 1 , Shofarul Wustoni 1 , Agus Wahyudi 2 , Ismunandar Ismunandar 1
1 Division of Inorganic and Physical Chemistry , Institut Teknologi Bandung, Bandung Indonesia, 2 R&D Center for Mineral and Coal Technology (Tekmira), Ministry of Energy and Mineral Resources, Bandung Indonesia
Show AbstractZeolites have found widespread applications nowadays. They have become important to more than just applicable in ion exchange, adsorption (separation) and catalytic chemistry but now, new fields such as microelectronic and metal diagnosis are opened for the development using zeolites. This is due to the fact that zeolites are able to serve as shape selective host for guest molecules. As located in the volcanic area, Indonesia has abundant source of naturally-occuring minerals. These natural minerals contain very low quality of zeolites, therefore in order to bring these minerals into high value, we have implemented seed-assisted synthesis to outcome only one selective zeolite into high quality. For this reason, we have selected the naturally-occuring minerals that are originated from Nanggung, Bogor having almost no crystallinity according to their X-ray diffraction (XRD) diffraction pattern. By utilizing these minerals as seed in such hydrothermal synthesis composition consisting of additional silica and alumina source, mordenite zeolite, one of zeolite types with medium silica content was selectively resulted. Characterization by XRD shows that this mordernite has high crystallinity and scanning electron microscopy (SEM) revealed the crystal morphology. We have concluded that this seed-assisted synthesis still requires additional silica and alumina source. Without these additional compounds, analcime zeolite is only the product that is considered to be less potential for applications than mordenite zeolite.
9:45 AM - D1.2
New Developments for Lignocellulosics - Nanocomposites with Low Carbon Footprint.
Alcides Leao 1 , Bibin Cherian 2 , Sivoney Souza 3 , Suresh Narine 4
1 Natural Resources, UNESP, Botucatu, Sao Paulo, Brazil, 2 Natural Resources, UNESP, Botucatu Brazil, 3 , UFABC, Santo Andre, Sao Paulo, Brazil, 4 Physics, Astronomy and Chemistry, Trent University, Peterborough, Ontario, Canada
Show AbstractMost of the natural fibers are grown in developing or under developed country worldwide, representing an importance source of income for millions of people around the world. The new developments of natural fibers toward the composites production will represent an increase in those economies. Composites reinforced with natural fibers at macro, micro and nano scales are opening new opportunities for may economical deprived areas that depend heavily on crop fibers. The present paper describes new applications of natural fibers in composites, technologies used for nanocellulose production and its application for automotive, biomedical and packaging industries. A carbon evaluation was made to complement its assessment related to biobase index. Pulp and paper primary sludge were treated with 2 % NaOH (fiber to liquor ratio 1:10) in an autoclave and kept under 20 psi pressures for a further period of 1 hour. Pressure was released immediately. The sludge fibers were removed from the autoclave and the fibers were washed in water until it was rid of alkali. The steam exploded fibers were bleached using a mixture of NaOH and acetic acid for the nanocellulose isolation.Microscopy techniques and X-ray diffraction were used to study the structure and properties of the prepared nanofibers and composites. The composition with 4 wt % cellulose was optimal and showed the highest strain-to-failure. The developed nanocellulose and its composites confirmed to be a very versatile material having wide range of biomedical applications and biotechnological applications, such as tissue engineering, drug delivery, Breathable Wound Dressing, Non Latex Condoms, Surgical Gloves, Surgical Gowns, OR Drapes, Hospital Mattresses, Hospital Sheets and Pads, Medical Bags, Tubing, Organ Retrieval Bags, Medical Disposables, Surgical Drapes and medical implants such as artificial heart diaphragms, heart valves, joint prostheses, vascular grafts, urethral catheters, mammary prostheses, penile prostheses, etc.
10:00 AM - D1.3
Hydrolytic Activity of Cellulose Nanocrystal.
Takeshi Serizawa 1 , Toshiki Sawada 1 2 , Masahisa Wada 3
1 Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo Japan, 2 Komaba Open Laboratory, The University of Tokyo, Tokyo Japan, 3 Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo Japan
Show AbstractCellulose is a linear polymer composed of D-glucose, which is linked each other with β1-4 bonds, and is the most abundant organic material in the biosphere. Natural cellulose shows high crystallinity, and is present as composites with other molecules such as hemicellulose, lignin, and/or proteins. Based on adequate purification processes, cellulose nanocrystal, which is stably dispersed in aqueous solution, can be obtained from various natural resources.We are interested in science and engineering of the interface between polymers and biomolecules. Particularly, we have demonstrated the presence of peptides that specifically recognize and bind to the surfaces of polymers, based on phage display methods that utilize peptide libraries prepared on genetically engineered viruses. Surprisingly, during binding analyses of peptides to cellulose nanocrystal, it was discovered that the amide linkage of the peptides bound onto the nanocrystal was hydrolyzed under ambient conditions, producing peptide fragments in the aqueous solution. The hydrolytic activity was independent of amino acid sequences of the substrate peptides. Once peptides bound onto the surface of cellulose nanocrystal, the amide linkages were hydrolyzed successfully.In order to characterize the hydrolytic activity of cellulose nanocrystals, hydrolysis of model organic substrates were analyzed quantitatively by monitoring the products. Not only the peptides but also the model substrates were hydrolyzed, suggesting versatile hydrolytic activities of cellulose nanocrystal. The order of hydrolytic rates were p-nitrophenyl acetate > monophosphate >>acetamide. The hydrolysis well followed a pseudo-first order reaction rate. The rate constant was obviously greater than that for spontaneous hydrolysis. Significantly, cellulose nanocrystals could be reused for repetitive hydrolysis with similar reaction rates, suggesting that the catalytic hydrolysis were preceded. The mechanism for the hydrolytic activity of cellulose nanocrystal will be proposed.
10:15 AM - D1.4
Stabilization of Tyrosinase for Humification Reaction.
Renu Yadav 1 , Swati Kotwal 2 , Nitin Labhsetwar 1 , Mrs. Sadhana Rayalu 1
1 Environmental Materials Divsion, National Environmental Engineering Research institute, Nagpur, Maharashtra, India, 2 University Department of Biochemistry, , RTM Nagpur University,LIT Premises,Amravati Road, Nagpur, Maharashtra, India
Show AbstractThe effect of climate change stemming from the significant increase in atmospheric CO2 levels has necessitated fixing or storing carbon as biomass in terrestrial ecosystems. Humus serves reservoir for carbon storage as an organic matter in soil. Humus is formed in soil in the presence of enzymes like tyrosinase and the process is known as humification. It shall resolve the problem of carbon depletion from soils with concomitant resolution of relentless build-up of the greenhouse gas such as carbon dioxide in the atmosphere. However, one of the major problems encountered with enzymatic reaction is the short life span and less stability of the enzyme in its free form. Efforts are being made at NEERI to overcome this problem; a new enzyme composite of nanometer scale is being developed by using a combination of stabilization and immobilization approach. This enzyme composite is referred to as single enzyme nanoparticle (SENs), wherein each enzyme is coated with organic / inorganic hybrid polymer of less than a few nanometers thick. The major advantages of immobilized SENs includes enzyme stabilization, enhanced reactivity, increased half life of enzyme with high surface area, and reduced mass transfer limitation. SEN-tyrosinase has been developed for its application in humification reaction in a view of CO2 sequestration through humus formation. Immobilization matrices such as mesoporous iron oxide, mesoporous manganese oxide, fly ash and bauxite residue are showing good activity for L-DOPA, used as substrate. The highest activity of 824 U/mg has been observed for SEN-tyrosinase immobilized on mesoporous iron oxide as compared to 625 U/mg for free enzyme. This may be attributed to synergistic effect between matrix and enzyme. SEN-Tyrosinase has been characterized for its elemental composition, protein content and surface morphology. Co-catalysis of humification occurs by three mechanisms involving physical stabilization of tyrosinase (formation of SEN and further immobilization it on different matrices), direct oxidation of the monomers (phenol), and promotion of the oxidation and condensation steps of alkaline pH. Although tyrosinase activity is greatest at neutral pHs, the large pH dependence of the condensation step drives the overall reaction to maximum rates under alkaline conditions. Substantial improvement in the half life period is expected, for which studies are in progress.
10:30 AM - D1.5
pH-Responsive Properties of Bio-Derived Glycolipids and Use as Structuring Agents for Material Synthesis.
Niki Baccile 1 , Florence Babonneau 1 , Bejoy Thomas 1 , Inge Van Boegaert 2
1 LCMCP, CNRS-UPMC, Paris France, 2 InBio, Gent University, Gent Belgium
Show AbstractThe capability of synthesizing natural compounds by some bacteria and/or yeasts is well-known since several decades and the applications of these products were mainly concentrated in the development of new cleansing, skin care products, drugs, polymers, etc... Nevertheless, some of them, and in particular glycolipids, have interesting physico-chemical properties in water. Rhamnolipids and sophorolipids, for instance, are microorganisms-derived water-soluble glycolipids which have the advantage of possessing an internal carboxilic acid function [1]. The physico-chemical behaviour of these biosurfactants is largely unknown but preliminary studies show pH-responsive micellization properties [2,3].Classical surfactants do not show specific pH-dependent aggregation properties, exception made for some classes of well-designed block copolymers based, for instance, on poly(acrylic acid) blocks.In this communication, we describe the pH-driven self-assembly, in aqueous solution, of functional glycolipids (sophorolipids). We show, mainly through Small Angle Neutron Scattering (SANS) and cryo-TEM experiments, the variety of meso and macro-assemblies and how to control them. We will discuss concentration and time-evolution effects and we will outline how the nature of the micellar/water interface changes as a function of pH. Finally, we will show how the properties of these fully natural molecules can be exploited in the synthesis of silica-based thin films and powders [3]. In particular, it will be interesting to see how slight changes in the initial conditions will lead to drastic changes in the material scaffold and porosity at different scales lenghts, from nano to macro. [1] I. N. A. Van Bogaert et. al Appl. Microbiol. Biotechnol., 2007, 76, 23–34[2] S. Zhou et al. Langmuir, 2004, 20, 7926-7932[3] N.Baccile et al., Green Chemistry, 2010, 12, 1564–1567
10:45 AM - D1.6
Morphology-Preserving Chemical Conversion of Intricate Three-Dimensional Micro/Nanopatterned Bio-Organic Structures into Multicomponent Oxide Compounds.
Jonathan Vernon 1 , Yunnan Fang 1 , Ye Cai 1 , Kenneth Sandhage 1
1 MSE, Georgia Institute of Technology, Atlanta, Georgia, United States
Show AbstractThe generation of nanostructured assemblies with complex (three-dimensional, 3D) self-assembled morphologies and with complex (multicomponent) tailorable inorganic compositions is of considerable technological and scientific interest. Self-assembled 3D inorganic templates, of biogenic or synthetic origin, have been converted into replicas comprised of numerous other functional inorganic materials (e.g., Si, Ag, Au, Pd, Pt, TiO2, ZrO2, SnO2, BaTiO3, Eu-doped BaTiO3, Mn-doped Zn2SiO4) by shape-preserving reaction-based and/or coating-based approaches.[1-9] Nature also provides a spectacular variety of biologically-assembled 3D organic structures with intricate, hierarchical (macro-to-micro-to-nanoscale) morphologies. In this presentation, a shape-preserving conformal coating and low-temperature (energy-efficient) reaction process for transforming bio-organic (sustainable) templates into freestanding 3D multicomponent oxide structures will be discussed. This conversion process consists of three general steps: (i) wet-chemical layer-by-layer deposition (to apply a thin, continuous, conformal oxide coating), (ii) organic pyrolysis (to selectively remove the bio-organic template), and (iii) hydrothermal reaction (to generate the desired nanocrystalline multicomponent oxide). This process is demonstrated by converting 3D macro/micro/nanostructured chitinous butterfly scales into barium titanate (BaTiO3). The phase and structural evolution at various steps of this process have been evaluated by electron microscopy, diffraction analyses, and raman spectroscopy. With proper attention to each step, this shape-preserving coat-then-react process may be used to generate macro/micro/nanostructured inorganic assemblies with a wide range of complex 3D morphologies and complex (multicomponent) functional oxide chemistries. [1] J.D. Berrigan, et al.. Adv. Funct. Mater., 21, 1693 (2011); [2] K.H. Sandhage, JOM, 62 [6] 32 (2010); [3] B. Hatton, et al., Proc. Nat. Acad. Sci., 107 [23] 10354 (2010); [4] G. Wang, et al., Adv. Funct. Mater., 19 [17] 2768 (2009); [5] Z. Bao, et al., Adv. Mater., 21 [4] 474 (2009); [6] R.F. Shepherd, et al., Adv. Mater., 20 [24] 4734 (2008); [7] Y. Cai, et al., J. Am. Ceram. Soc., 90 [4] 1304 (2007); [8] Z. Bao, et al., Nature, 446 [3] 172 (2007); [9] K.H. Sandhage, et al., U. S. Patents 7,615,206 (2009), 7,393,517 (2008), 7,204,971 (2007), 7,067,104 (2006).
D2: Synthetic Approaches
Session Chairs
Tuesday PM, November 29, 2011
Back Bay B (Sheraton)
11:30 AM - **D2.1
About the Recent Advances in Mechanochemical Approach to Materials Design.
Viktor Balema 1
1 Materials Science, Sigma-Aldrich Corp., Milwaukee, Wisconsin, United States
Show AbstractThe presentation addresses an experimental approach which proved to be indispensable in basic and applied materials science R&D—the preparation and modification of solid materials on molecular and nano-level using high-energy mechanical processing. This approach, also know as mechanochemistry, offers an extremely convenient way of making novel materials and studying chemical transformations that take place in solids under solvent-free conditions. Recent research suggests that exact mechanisms of mechanochemical processes should be determined on a case-by-case basis. It also appears that mechanochemical processes in solids can be driven by a variety of deformations and the high pressure, generated in the material during milling or grinding.
12:00 PM - D2.2
Hydrogen Storage Properties of Nanostructured Graphite-Based Materials.
Yinghe Zhang 1 , David Book 1
1 , University of Birmingham, Birmingham United Kingdom
Show AbstractIn 1999, Orimo[1] reported that nanostructured graphite produced by milling could absorb up to 7.4 wt% hydrogen. However, high temperatures (up to 600 K) were then required to release this hydrogen, and it was not reversible. In 2005, Ichikawa et al[2] reported that the addition of LiH introduces a degree of reversibility (i.e. allows some hydrogen re-absorption). Ball-milled graphite with Fe (1 at%) (10 bar H2, 80 h) was found to store more hydrogen than pure graphite milled under the same conditions[3]. However, for both these additions, methane was also released during desorption, which will prevent long-term reversibility.In this work, the effect of milling conditions and additions on the microstructure and hydrogen storage properties of graphite milled in a tungsten carbide pot was investigated using TGA, mass spectrometry, XRD, SEM, TEM, Sieverts-PCT and Raman spectroscopy. The TGA and MS results showed that, for a graphite sample milled in hydrogen for 10 hours, the amount of hydrogen desorbed was about 5.6 wt%, and the onset desorption temperature was about 400°C. No methane release could be detected up to 12 hours milling time. The physical properties have been characterised by HRTEM and Raman spectroscopy as a function of milling conditions. HRTEM showed that the interlayer distance changed with milling (Fig. 1). This work discusses how the milling conditions and the type of additions (i.e. LiH, Fe), effect both the structure of the graphite samples and their hydrogen storage properties.References[1]S. Orimo et al, Applied Physics Letters, 1999, 75, 3093-3095.[2]T. Ichikawa et al, Applied Physics Letters, 2005, 86.[3]H. Miyaoka et al, J Alloy Compd, 2010, 507, 547-550.
12:15 PM - D2.3
Synthesis of Crystalline, Metastable Solid Ionic Conductors via a Solution-Based Routine.
Wujun Fu 1 , Zengcai Liu 1 , Zhan Lin 2 , Zili Wu 3 , Xiang Yu 1 , Andrew Payzant 2 , Nancy Dudney 2 , Jim Kiggans 2 , Jane Howe 2 , Kunlun Hong 1 , Chengdu Liang 1
1 Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 2 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 3 Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
Show AbstractSolid electrolytes attract great interests in battery research for their potential use in the next generation of high energy batteries such as lithium-air and lithium-sulfur batteries. In spite of their salient advantages of broad electrochemical window, enhanced safety, and alleviated environmental concerns, the known solid electrolytes have limited use in batteries because of their inadequate ionic conductivity at ambient temperature. New materials with high ionic conductivity are highly desirable in battery research. Among a broad variety of materials showing ionic conductivities, lithium sulfide-based solid electrolyte, in particular, the binary Li2S-P2S5 glass system, which exhibits high lithium ionic conductivity up to 10-3 S/cm and wide electrochemical window over 5 V, attracted much attention recently. The binary Li2S-P2S5 electrolytes are generally synthesized via conventional solid-state synthesis at extremely high temperatures (up to 900 C) under vacuum or through long-period mechanical milling by using a ball mill apparatus. In some cases, materials of high ionic conductivity are metastable phases. The harsh synthesis conditions of high temperature exclude the solid-state synthesis of metastable phases. In addition, some solid-state routines are neither environmental friendly nor suitable for mass production. From the sense of synthesis, a facile, scalable routine, which can precisely control the composition and phase of the final products, is highly desired. Herein, we reported a facile, solution-based synthesis method by using organic solvent as the template to guide the formation of the pure, metastable Li2S-P2S5 crystalline phase. The electrochemical impedance measurements indicated that the prepared crystalline Li2S-P2S5 phase is an ionic conductor exhibiting Li+ conductivity up to 10-5 S/cm at room temperature. This facile solution-based synthesis method is a boon to the pursuit of novel solid lithium superionic conductors.
12:30 PM - D2.4
Ajaokuta Blast Furnace’s Slag as Spin off Materials for Industrial Development.
C. Ocheri 1 , J. Agboola 2
1 Foundry Shop, Ajaokuta Steel Company Limited, Ajaokuta, Kogi Nigeria, 2 Mechanical Engineering Department, Federal University of Technology, Minna Nigeria
Show AbstractSlag is the by-product of smelting ore to purify metals. They can be considered to be a mixture of metal oxides; however, they can contain metal sulfides (also matte) and metal atoms in the elemental form. While slags are generally used as a waste removal mechanism in metal smelting, they can also serve other purposes, such as assisting in smelt temperature control and minimizing re-oxidation of the final liquid metal product before casting. The design of Ajaokuta Steel Company Limited is based on the Blast Furnace –Basic Oxygen Furnace (BF-BOF) process route for the production of iron and steel. In the production process of the blast furnace, molten iron and slag materials are produced. Molten iron will be transferred to the Steel Making Shop for the production of steel, while the slag materials produced can serve as spin off materials for industrial development. This paper therefore focus on the slag materials which is waste materials from smelting: (fused glassy material that is produced when a metal is separated from its ore during smelting). Some methods of processing slag materials for industrial development were discussed; the chemical compositions of slag from the blast furnace were brought to the fore. Applications and uses of slag materials were discussed with emphasis to the building, and construction industries .Slag can also be used as sound absorber in reducing noise and treating of industrial water. Some suggestions and recommendations were proffered for the use of slag materials for industrial development in Nigeria.
12:45 PM - D2.5
Syntheses and Characterization of CdSiO3 in Low Temperatures by Molten Salt.
Leonardo Santana 1 , Flávio Vichi 1 , Erick Souza 1
1 Fundamental Chemistry, USP, São Paulo, São Paulo, Brazil
Show AbstractIon-exchange reactions are used in the synthesis of many important materials. While these reactions are very well known in the gaseous and liquid states, they have received relatively little attention in the solid state. Recently, low temperature reactions have been studied as an alternative to conventional, energy-intensive processes. In this context, soft chemistry routes based on hydrothermal and microwave radiation have been proposed.An interesting alternative, which has not been as extensively explored as others, is the molten-salt synthesis, in which a molten salt flux acts either as a solvent or as a reactant. Cadmium metasilicate (CdSiO3) is an important matrix for use in devices having persistent luminescence, due to its good chemical and physical stability, ease of preparation, and low cost. Therefore, interest in this type of material has been increasing recently.1 Traditionally, cadmium metasilicate has been prepared by solid state synthesis, yielding pure, crystalline CdSiO3 at temperatures ranging from 900 – 1050 °C. However, these preparations involve long periods of ball-milling followed by long heating times, typically from 5 to 12 h. Moreover, materials prepared this way exhibit large highly aggregated particles.1Sol-gel routes, which involve the use of tetraethylorthosilicate (TEOS) as the silicon precursor, have also been proposed, but pure CdSiO3 is obtained in pure form only after heat treatments above 870 °C for several hours, also yielding large aggregated particles.In this contribution we report the successful preparation of single-phase CdSiO3 nanowires and nanorods at temperatures as low as 360 °C. Cadmium chloride and cadmium nitrate were used as a molten reactants. The resulting materials were characterized by x-ray diffraction (XRD), focused ion beam (FIB) microscopy, field-emission scanning electron microscopy (FESEM), surface area by nitrogen adsorption (BET). The characterization confirms the preparation of pure, single-phase, crystalline CdSiO3 nanoparticles in the form of nanowires and nanorods.1Qu, X.; Liu, W.; Su,G.;Qu, H.; Xu, C. J. Alloys Comp. 2009, 484, 641,644
D3: Nanomaterials/Composites
Session Chairs
Tuesday PM, November 29, 2011
Back Bay B (Sheraton)
2:30 PM - **D3.1
Making Composites without Matrix.
Ton Peijs 1
1 Centre for Materials Research, Queen Mary University of London, London United Kingdom
Show AbstractOver the last decennia mono-material concepts such as self-reinforced polymer composites based on oriented polymer fibres or tapes bonded together by a polymer of similar origin have emerged as promising new materials for lightweight structures with added ecological benefits due to their good recyclability. This presentation will report on recent developments in the field of self-reinforced polymer composites including systems based on PP, PE, PET, PLA, PPTA and cellulose. Next to environmental benefits as a result of their mono-material character which facilitates recyclability, and their lightness due to the replacement of (heavy) glass fibres by lightweight polymer fibres, these materials have also shown to exhibit competitive mechanical properties compared to their traditional counterparts. The main reason for their excellent mechanical properties is often the high reinforcement content in these types of composites. Since processing of these materials is based on non-traditional – non-impregnation based – processes their reinforcement content is not limited to the traditional 50-60 vol.%. Instead fibre volume fractions in these materials can often exceed 80-90 vol.% (and in some cases even 100%), giving them their advantageous mechanical characteristics.
3:00 PM - D3.2
Synthesis of Macroporous Calcium Carbonate/Magnetite Nanocomposites and Their Application in Photocatalytic Water Splitting.
Yi-Yeoun Kim 1 , Dominic Walsh 2 , Fiona Meldrum 1
1 School of Chemistry, University of Leeds, LEEDS United Kingdom, 2 School of Chemistry, University of Bristol, Bristol United Kingdom
Show AbstractWe report a simple and versatile method which concurrently achieves structural control and introduces functionality into CaCO3 microparticles. The work investigates the microwave-induced metamorphosis of highly hydrated calcium carbonate hexahydrate (ikaite) crystals incorporating microwave-absorbing superparamagnetic magnetite nanoparticles, and demonstrates that unique porous vaterite/magnetite composite crystals can be synthesised using this route. That the incorporporated nanoparticles are accessible and active for reactive processes is demonstrated through the exploitation of the magnetite nanoparticles/calcium carboante microparticles in photocatalytic water oxidation, where it is shown that they function as an effective, convenient and reusable material.Carboxymethyl dextran-magnetite (CMD-Mag) was prepared by a combined dextran carboxylation and magnetite precipitation reaction. Then, calcium carbonate was precipitated in a solution cooled to 0-3oC by precipitation of CaCl2 with (NH4)2CO3 in the presence of CMD-Mag nanoparticles. The precipitate was filtered cold before microwaving for 5 minutes. The magnetite cores of these particles were 1-4 nm in diameter and had a hydrodynamic diameter of 23 nm after coating with CMD. Coating with CMD stabilizes the particles in the crystal growth solutions and promotes absorption to the CaCO3 crystals, thereby facilitating encapsulation. The first phase precipitated in the presence of CMD-mag was amorphous calcium carbonate (ACC), which gradually transformed to CaCO3.6H2O crystals with hexagonal, plate-like morphologies in a cold water environment. Interestingly, magnetite incorporation significantly stabilized the CaCO3.6H2O crystals against crystallisation. Further, when these crystals were washed and then microwaved to dryness, their original morphologies were retained and Raman analysis and XRD showed them to be entirely polycrystalline vaterite. Imaging of these vaterite crystals showed that they displayed remarkable, open microstructures comprising 200 nm segregated columns formed from packed nanocrystals of vaterite, where the entire internal surface area of the porous CaCO3 particle is intimately associated with magnetite nanoparticles. BET measurements gave a surface area of 12.65 m2/g. In addition to the orange colour, the presence of Fe was quantified at 3.22 wt% using atomic absorption spectroscopy, which corresponds to 4.44 wt% magnetite and 9.87 wt% CMD-mag. The work additionally demonstrates that the Calcium carbonate/magnetite particles, due to Fe ion release, are effective in photocatalytic water oxidations that liberate O2. It is envisaged that this methodology is not unique to this CaCO3/magnetite system, but could be applied to the straightforward synthesis of a range of composites containing microwave absorbing nanoparticles. Further work is currently underway investigating alternative hydrated crystals and an extended range of microwave-active nanoparticles.
3:15 PM - D3.3
Characterization of an Ionically Cross-Linked Polymer-Clay Nanocomposite Prepared by Green, In Situ Melt Polymerisation of l,d-lactide by Stearate-Treated Layered Double Hydroxide.
Edward McCarthy 1 , Mauro Zammarano 2 1 , Gale Holmes 1 , John Howarter 1 , Yeon Kim 2 , Ryan Nieuwendaal 3 , David VanderHart 3 , Paul Maupin 4 , Paul Trulove 5 , Jeffrey Gilman 1
1 Sustainable Polymers Group, Polymer Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States, 2 Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States, 3 Electronics Materials Group, Polymer Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States, 4 Office of Science, Department of Energy, Germantown, Maryland, United States, 5 Department of Chemistry, United States Naval Academy, Annapolis, Maryland, United States
Show AbstractAn organic-inorganic composite of poly(lactic acid), PLA, and magnesium aluminum stearate-intercalated layered double hydroxide, Mg Al LDH-St, has been produced by in-situ bulk polymerisation of l,d lactide monomer within nanolayers of Mg Al LDH-St without the use of an additional metal octanoate catalyst (e.g. tin) or solvent. An average polymer mass yield of 88% has been determined for the polymerisation, under an optimal clay loading of 5% LDH-St by mass.In this work we present thermogravimetric, spectroscopic and molecular mass data to investigate whether the formation of PLA is by co-ordination insertion ring-opening bulk polymerisation, (CIROP), catalysed principally and directly by layered double hydroxide at the clay surface, or by other competing mechanisms such as anionic polymerisation, (AROP), by free salts in the melt or polycondensation of hydrolysed lactide dimer facilitated by trace moisture. In addition, scanning electron microscope images of extract residues confirm the formation of an insoluble gel fraction within the composite suggesting cohesive ionic crosslinking between PLA and Mg Al LDH-St, strengthening the case for substantial CIROP at the clay surface. Solid state C-13 NMR and XPS characterization of the reaction components will also be presented.Lastly, initial rheology of the reaction product, as well as its soluble and insoluble gel polymer fractions obtained by methylene chloride extraction, is discussed to determine the extent of reinforcement provided by the gel fraction of the product.In the future it is intended to more fully characterise the nature of the integration between polymer and clay in terms of chemical bonding and molecular mass distribution as well as making further determinations of key mechanical properties using melt rheology and dynamic mechanical analysis.
3:30 PM - **D3.4
Design and Fabrication of Composite Nanostructures.
Hua Chun Zeng 1
1 , NUS, Singapore Singapore
Show AbstractDiscrete nanostructures have a limited scope of applications, due to the difficulty in separation and recovery after use. Furthermore, a functional nanostructure nowadays is normally not a single-phase solid, but a highly organized multicomponent materials system. To prepare composite nanostructures, architectural aspects of design and synthesis need to be addressed, because the ways of compositional and structural organizations in the final products will give profound impacts on their ultimate performance. Therefore, our current research efforts are mostly directed to chemical methods for self-assembly of functional materials into complex nanostructures, which will be the subject of this presentation. We have recently synthesized a range of functional nanostructures with architectural designs. In these syntheses, most processing steps were carried out in liquid media under mild reaction conditions.1-7 Similar to organic synthesis, for example, various kinds of organic ligands, surfactants and inorganic/organic salts were utilized in our experiments in order to create steric hindrance effects, binding interactions, and control of surface reactivity for directional growth and organization of nanomaterials.1-7 Therefore, unlike solid-solid or gas-solid reactions, synthetic processes and assemblies conducted in solution media would then be analogous to the conventional total synthesis of organic molecules.1 In our research, preparative processes, size manipulation, surface functionalization, catalytic reactions, and reactivation of nanoparticles inside the nanostructures are being investigated. To make composite nanostructures usable in real reaction environments, for instance, new processing schemes for complex nanostructures with permanent engagement among primary building units have been developed. Tiered organizations among different components have also been addressed in several model systems, including architecture of interior space. These highly organized nanostructures have shown promising performances in some new applications.References1. H.C. Zeng, Journal of Materials Chemistry, 21 (2011) 7511–7526. 2. T.T. Chng, L. Polavarapu, Q.H. Xu, W. Ji and H.C. Zeng, Langmuir, 27 (2011) 5633–5643.3. C.C. Li and H.C. Zeng, Journal of Materials Chemistry, 20 (2010) 9187-9192. 4. M.L. Pang, J.Y. Hu and H.C. Zeng, Journal of the American Chemical Society, 132 (2010) 10771-10785. 5. K.X. Yao, X.M. Yin, T.H. Wang and H.C. Zeng, Journal of the American Chemical Society, 132 (2010) 6131-6144.6. M.L. Pang and H.C. Zeng, Langmuir, 26 (2010) 5963-5970.7. S.M. Zhang and H.C. Zeng, Chemistry of Materials, 22 (2010) 1282-1284.
D4: Nanomaterials/Metals
Session Chairs
Tuesday PM, November 29, 2011
Back Bay B (Sheraton)
4:30 PM - D4.1
Syntheses of Metal Nanoparticles in Ionic Liquids.
Silke Behrens 1 , Sarah Essig 1
1 , Karlsruhe Institute of Technology, Karlsruhe Germany
Show AbstractRecently, room-temperature ionic liquids have attracted great interest, e.g. as reaction medium, reactant or template for the synthesis of inorganic nanomaterials. Ionic liquids are molten organic salts with low melting points (<100°C). They are well known for their low vapor pressure, good thermal stability, and high polarity. Their physico-chemical properties such as viscosity, vapor pressure, polarity, and solvent miscibility may be further adjusted by choice of the cation, anion and by the length of the lateral alkyl side chains of the hetercyclic ring. Hence, ionic liquids offer an interesting combination of novel properties that enlarge the possibilities of classic nanomaterial synthesis. Ionic liquids are shown to provide a favorable environment for the synthesis of magnetic metal nanoparticles without adding any further stabilizing ligands. The nature of the applied ionic liquid influences nanoparticle nucleation and growth and may be recycled after synthesis. Herein, we describe a simple and “green” method for the synthesis and tailoring of nanoparticle-based magnetic fluids in divers carrier liquids.
4:45 PM - D4.2
One-Step Synthesis of Stable Metallic Nanoparticles on Eco-Friendly Ionic Liquids.
Anantha No LAST NAME 1 , Wang Xiu 1 , Chee Cheong Wong 1
1 School of Materials Science & Engineering , Nanyang Technological University, Singapore Singapore
Show AbstractMetallic nanoparticles are more often obtained by chemical - decomposition or reactive techniques, involving the extensive usage of harmful reducing or stabilizing agents. A facile green synthesis technique resulting in readily exploitable nanoparticle dispersion in ionic liquid without the use of any additional agents is reported here. 1-Propyl- 3- Methyl Imidazolium Iodide (PMIM-I) is a non-volatile, thermally stable and non-toxic ionic liquid. This eco-friendly liquid is used as the substrate for thermal evaporation of gold to obtain stable gold nanoparticles. On being examined by Transmission Electron Microscopy and Ultraviolet-Visible spectroscope the high monodispersity in their sizes was revealed. The byproduct free, ‘clean’ processing technique helps in obtaining un-contaminated particles. The thermal evaporation method used (for the generation of metallic vapor) plays a significant role in the difference in kinetics of the formation and growth of nanoparticles, unlike the widely reported sputtering technique for vapor generation. The formed particles are deposited only on the top surface of the liquid as observed through optical microscope, leaving the bulk of the liquid devoid of any particles. Thus the nucleation and growth of the particles is said to have occurred by surface diffusion process only. Further experimental investigations carried out for varied viscosities of ionic liquids under diverse levels of supersaturations were in agreement with the primary observation. A deeper investigation into the formation kinetics has the potential application for synthesizing other nanomaterials via this environmental friendly, straightforward approach without polluting the surroundings with toxic reagents.
5:00 PM - D4.3
Facile One-Step Synthesis of Alloyed/Core-Shell Pd/Pt Nanoparticle Assembles by Tri-Block Copolymers.
Fang-ching Chang 1 2 , Yen-Cheng Li 1 , Ren-Jye Wu 1 , Chun-Hua Chen 2
1 Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu Taiwan, 2 Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu Taiwan
Show AbstractThe morphology of nanoparticles is one of the most critical issues to the performance of catalysts. In this work, a one-step synthesis of a series of morphologically-controlled Pd and Pd/Pt nanoparticle assembles has been newly designed and achieved by reducing PdCl2 and H2PtCl6 reagents in aqueous Pluronic F127 (polypropylene oxide-polyethylene oxide-polypropylene oxide triblock copolymer, PEO99PPO69PEO99) gels with the appearance or absence of L-ascorbic acid (AA). The F127 acts as not only a reductant, but most importantly, a tunable nanoreactor since the high-concentration F127 (30 wt%) spontaneously leads a face-center-cubic packing of spherical micelles, consisting of a relatively compact PPO core and a well solvated PEO shell, at room temperature. It has been found that the well assembled F127 micelles indeed contribute the extremely uninform aggregated morphologies observed and AA seems to affect the reduction locations, i.e. the PEO shells within micelles or spaces between micelles. The further fine structure of the formed nanoparticle assembles were qualitatively and quantitatively characterized by x-ray diffraction, small-angle x-ray scattering, transmission electron microscopy and UV-vis spectra. In addition, the catalytic performance of the synthesized Pd and Pt/Pd nanoparticle assembles will also be discussed.
5:15 PM - D4.4
One Pot Synthesis of Gold NanoNachos for Biotechnological Applications.
Beatriz Pelaz 1 , Pablo del Pino 1 , Valeria Grazu 1 , Wolfgang Parak 2 , Jesus de la Fuente 1
1 Instituto de Nanociencia de Aragon, University of Zaragoza, Zaragoza, Zaragoza, Spain, 2 , University of Marburg, Marburg Germany
Show AbstractIn the last years, gold nanoparticles have found a great deal of interest in the area of nanoscience. This is due to the interesting physicochemical properties that these materials bear including biocompatibility, localized surface plasmons or ease of biofunctionalization by means of molecules bearing thiol groups. More recently, asymmetric gold nanoparticles (NPs) such as nanorods, triangular nanoprisms or core-shell dielectric-gold NPs have achieved an increasing popularity. This trend is mainly originated from the absorption band that they present in the NIR range of the electromagnetic spectrum; NIR excitation of NPs is the most favorable scenario for biomedical applications since NIR radiation has a suitable penetration depth in biological tissues. Upon excitation with NIR radiation, these asymmetric materials can release heat to their most immediate vicinity. However, most of the methods to produce NIR absorbing Au NPs relies on challenging synthesis with several steps and/or seed-mediated approaches with cetyltrimethylammonium bromide (CTAB) as a surfactant. To the best of our knowledge, CTAB is the most widely used and convenient surfactant to synthesize Au nanorods and nanoprisms although it is a well-known toxic cationic surfactant. The development of straightforward and scalable synthesis methods of non-cytotoxic Au anisotropic NPs is of the most importance.Here we describe a simple and straightforward synthesis route to produce gold triangular nanoprisms that we have called NanoNachos (NNs) due to the characteristic shape they present. While keeping the thickness of NNs constant, the edge length and therefore the aspect ratio can be varied by adjusting the final concentration/molar ratio of gold salt and reducing agent. Thus, the LSPR of NNs can be tuned along the NIR range. In contrast to most of the previously reported methods to produce Au nanoprisms in high yield, CTAB is not required in our method. The feasibility of NNs as transducers for photothermal therapy is proven at the single cell level. Besides the simplicity of the synthesis method, avoiding CTAB makes NNs very interesting probes for applications in nanomedicine.
5:30 PM - D4.5
Synthesis of Dendrimer-Stabilized Gold Nanoparticles Using Green Methods.
Oscar Olea-Mejia 1 , Alfredo Vilchis-Nestor 1 , Marco Camacho-Lopez 2 , Oscar Olea-Cardoso 3 , Jimena Hernandez-Cejudo 1
1 Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM. Facultad de Química, Universidad Autónoma del Estado de México, Toluca, Mexico, Mexico, 2 Laboratorio de Investigación y Desarrollo de Materiales Avanzados. Facultad de Química, Universidad Autónoma del Estado de México, Toluca, México, Mexico, 3 Facultad de Química, Universidad Autónoma del Estado de México, Toluca, Mexico, Mexico
Show AbstractGold nanoparticles were successfully obtained using two different green methods. The first one was the laser ablation of a gold rod immersed in a liquid; the second was the reduction of a metallic salt using a natural bioreductor. These techniques were carried out in a dendrimer solution in order to control the shape and size of the nanoparticles as well as for their stabilization. Our samples were characterized by UV-Vis spectroscopy and by Transmission Electron Spectroscopy (TEM). It was observed that without dendrimer it is possible to obtain nanoparticles with an average size of around 10 nm depending on the method used. We have seen an effect of the concentration and the type of dendrimer used in the properties of the particles. When adding dendrimer to the system, it is possible to reduce the particle size up to 3 nm as well as narrow their size distribution. The particle shape is also affected by the dendrimer since more homogeneous spherical nanoparticles are formed. Some of the nanoparticle colloidal solutions are stable for a few weeks while other precipitate a few days after the synthesis.
5:45 PM - D4.6
Size Tunable Continuous Ultrasonic Sonoelectrodeposition of Submicron Metallic Particles.
Joseph Reneker 1 , Taofang Zeng 1
1 Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractTypical ultrasonic sonoelectrodeposition particle synthesis methods use out of phase pulses of electric current and ultrasound pulses. In this technique, a current pulse deposits particles on a surface, which are subsequently removed with a burst of ultrasonic energy. Such out of phase methods preclude potentially useful processes which occur under simultaneous application of ultrasonic and electric energy. We have studied metallic particles electrodeposited under continuous ultrasonic irradiation. Results have indicated a mechanism for particle growth that is not present in conventional out of phase pulsed electrodeposition. The effect of this mechanism on the size distribution of electrodeposited particles was studied. A continuous sonoelectrodeposition reactor design is proposed to take advantage of this growth mechanism to enable size tunable synthesis of submicron particles. This technique should be applicable to the wide variety of particles already synthesized by pulsed sonoelectrodeposition. As in conventional commercial electroplating, electrolyte solutions can be reusable. This is an affordable and environmentally friendly method for producing bulk quantities of submicron nanostructured particles.
Symposium Organizers
" " " Brookhaven National Laboratory
Mato Knez Max Planck Institute of Microstructure Physics
Stanislaus S. Wong State University of New York at Stony Brook
Hongjin Fan Nanyang Technological University
Woo Lee Korea Research Institute of Standards and Science (KRISS)
D9: Poster Session: Sustainable Synthesis, Characterization, and Application
Session Chairs
Mato Knez
Woo Lee
Stanislaus Wong
Wednesday PM, November 30, 2011
Exhibition Hall C (Hynes)
D5: Nanomaterials/Catalysts
Session Chairs
Wednesday PM, November 30, 2011
Back Bay B (Sheraton)
9:30 AM - **D5.1
Synthesis of Nanostructured Catalysts for Biomass Conversion.
Christopher Marshall 1 , Eric Stach 2 , Fabio Ribeiro 2 , Jeffrey Greeley 1 , Justin Notestein 3 , Kenneth Poeppelmeier 1 3 , Larry Curtiss 1 , Mayfair Kung 3 , Peter Stair 1 3 , Randy Winans 1 , SonBinh Nguyn 3 , Jeffrey Elam 1
1 Energy Systems Division, Argonne National Laboratory, Argonne, Illinois, United States, 2 , Purdue University, West Lafayette, Indiana, United States, 3 , Northwestern University, Evanston, Illinois, United States
Show AbstractThe successful transition to an energy economy based on biomass will require radical advances in catalyst science. This challenge demands a new paradigm in catalyst synthesis whereby inorganic components can be assembled at the atomic scale to yield complex, multifunctional catalysts rivaling Nature’s enzymes in their specificity. To this end, we have developed a novel approach combining templated synthesis for shape-selectivity with the atomically-precise positioning of discrete functionalities. In this approach we begin with a supporting scaffold for catalyst growth upon which we chemically attach molecular templates. Next, atomic layer deposition is used to build a structure around each template in an atomically precise, layer-by-layer fashion where the thickness and composition can be tuned at each layer. Finally, the template is removed yielding a “nanobowl” defining a structured catalytic environment. The molecular template can be synthesized to contain bulky organic ligands surrounding a catalytic atom or cluster which remains anchored to the bottom of the bowl after ligand removal. Furthermore, one or more layers in the bowl wall can be selected to serve as a co-catalyst (e.g. Lewis acid group) positioned at a well-defined distance from the catalyst at the bottom of the bowl. This presentation will review our recent progress synthesizing, characterizing, modeling, and testing these unique catalytic materials.
10:00 AM - D5.2
Shape-Controllable Synthesis and Facet-Dependent Catalytic Property of Platinum Alloy Nanoparticles.
Jianbo Wu 1 , Rajinder Singh 1 , Miao Shi 1 , Isthier Chaudhury 1 , Hong Yang 1
1 Chemical Engineering, University of Rochester, Rochester, New York, United States
Show AbstractSince the surface structure of metal alloy nanocrystals plays an important role in catalytic activity and selectivity, shape-controlled synthesis of metal alloy nanostructures has attracted increasing attention owing to their potential use as highly active heterogeneous catalysts in fuel cells, batteries, and other alternative energy systems. However, the shapes controlled by the current methodologies are limited by and heavily relied on the materials. Recently, we report a series of shape-controlled Pt-M alloy nanocrystals with a wide range of compositions via a versatile synthetic approach under the same CO-assisted reduction condition [1]. Among them, {111} faceted octahedron shows 50% higher in oxygen reduction specific activity over {100} faceted cubes for Pt3Ni systems [1-2]. In this presentation, I will discuss the selectivity of binding of CO between {111} and {100} Pt surfaces. Furthermore, a newly developed monodisperse shape with highly twinned planes has also been obtained. An oxygen reduction reaction (ORR) specific activity of highly twinned facets is observed. Surface treatment instead of annealing will also be discussed to illustrate the need for proper activation of the catalysts made in solution phase.References:[1] Wu, J.; Gross, A.; Yang, H., Shape and Composition-Controlled Platinum Alloy Nanocrystals Using Carbon Monoxide as Reducing Agent, Nano Lett. 2011, 11, 798-802.[2] Wu, J.; Zhang, J.; Peng, Z.; Yang, S.; Wagner, F. T.; Yang, H., Truncated octahedral Pt3Ni oxygen reduction reaction electrocatalysts, J. Am. Chem. Soc. 2010, 132, 4984–4985.
10:15 AM - D5.3
Remarkable Effect of Bimetallic Ni-Ru Catalysts in Dehydrogenation of Ammonia Borane.
Guozhu Chen 1 , Stefano Desinan 1 , Renzo Rosei 2 , Federico Rosei 1 , Dongling Ma 1
1 Institut National de la Recherche Scientifique, Quebec university, Varennes, Quebec, Canada, 2 Physics Department, Trieste University, Via Valerio Italy
Show Abstract Bimetallic nanoparticles (NPs) exhibit promising properties, quite distinct from those of their monometallic counterparts. However, the synthesis and hence the realization of desirable properties of these bimetallic structures are still quite challenging since their structure and composition are influenced by many parameters. It is thus of interest to rationally design these NPs, to identify appropriate synthetic routes to achieve controlled synthesis, and furthermore to gain full knowledge of their structure and composition in order to realize their high potential. Herein, we report, for the first time, the synthesis of Ni@Ru core-shell NPs using a wet-chemistry method. [1] The structure was thoroughly investigated using an array of characterization tools. The Ni@Ru NPs show remarkable performance in the hydrolysis of amonia borane. Their catalytic activity outperforms recently reported bimetallic catalysts in terms of the turnover frequency, including those based on the most active noble metals, such as platinum. The high catalytic activity is mainly attributed to the high surface area owing to the presence of many tiny 2-3 nm Ru NPs on the surface of Ni; the synergistic effect between Ni and Ru also cannot be excluded. Moreover, Ni@Ru NPs show a saturation magnetization and weak hysteresis similar to those of Ni NPs, indicating they basically remain the superparamagnetic behavior of the Ni core. Our recent results on the synthesis of novel Ni-Ru alloy NPs and their interesting catalytic properties will also be presented. References:[1]. Chem. Commun., 2011, 47, 6308-6310
10:30 AM - D5.4
Nanoscale β-Sn1−nWO4●nSn(hp) – A Highly Efficient Daylight-Driven Photocatalyst.
Jan Ungelenk 1 , Claus Feldmann 1
1 Inorganic Chemistry, Karlsruhe Institute of Technology, Karlsruhe Germany
Show AbstractPhotocatalysis is a powerful technology for water treatment including decomposing organic pollutants and crucifying germs. However, the standard material TiO2 is limited to UV-light whereas many visible-light-sensitive photocatalysts contain harmful (e.g. BiVO4) or high-cost elements (e.g. InNbO4) [1, 2]. Considering this, β-SnWO4 – the bright-yellow high temperature phase of SnWO4 – appears much more suitable. Both theoretical considerations as well as tests on bulk material indicate promising good photocatalytic properties [3, 4]. Yet, β-SnWO4 has not been available on the nanoscale.Here, we report on bright-yellow tin tungstate-based nanoparticles that are able to degrade various organic dyes 5 - 10 times faster under simulated daylight than commercially available TiO2 (Degussa P25) [5]. Moreover, the material works more efficient than BiVO4, the most important visible-light-sensitive photocatalyst to date. The nanomaterial is easily obtained via quick nucleation from aqueous solutions utilizing efficient electrostatic stabilization. Conducted at ambient temperature, the reaction yields a remarkably, self-adjusting phase composition of incipient crystalline yellow β-SnWO4 nanoparticles containing a certain amount of the cubic high-pressure phase of tin: Sn(hp). The presence of elemental tin might be beneficial with concern to the photocatalytic properties, supposably by providing an efficient charge separation. Diverse organic dyes including phenothiazine dye methylene blue, triphenylmethane dye basic green 4 and azo-dye methyl red are decomposed rapidly. The nanoparticles exhibit an average diameter of 20 nm, a low degree of agglomeration and a high specific surface (71 m2/g). Recycling experiments proved phase stability and reusability. Notably the presented preparation is both low-cost and truly sustainable since it is energy saving and can be done without any toxic elements, organic solvents or additives. As the chosen model organic dyes are classified as hazardous to water and to health, the detoxification potential of β-Sn1−nWO4●nSn(hp) becomes obvious.[1] A. Fujishima, X. Zhang, D. A. Tryk, Surf. Sci. Rep. 2008, 63, 515 (Review).[2] H. Goesmann, C. Feldmann, Angew. Chem. Int. Ed. 2010, 49, 1362 (Review).[3] A. Walsh, Y. Yan, M. N. Huda, M. M. Al-Jassim, S. H. Wei, Chem. Mater. 2009, 21, 547.[4] I. S. Cho, C. H. Kwak, D. W. Kim, S. Lee, K. S. Hong, J. Phys. Chem. C 2009, 113, 10647.[5] J. Ungelenk, C. Feldmann, Appl. Catal. B 2011, 102, 515.
10:45 AM - D5.5
Characterization of Nano-Crystalline Structure of TiO2 Supported Manganese Oxide Catalysts by Raman Spectroscopy: Correlation between Structure and Catalytic Activity.
Sergey Mamedov 1 , Padmanabha Reddy Ettireddy 2 , Punit Boolchand 3 , Panagiotis Smirniotis 4
1 , Horiba Jobin Yvon Inc., Edison, New Jersey, United States, 2 , Cummins Emission Solutions , Columbus, Indiana, United States, 3 School of Electronics and Computings Systems, University of Cincinnati, Cincinnati, Ohio, United States, 4 College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio, United States
Show AbstractA series of TiO2 supported manganese oxide catalysts were studies by Raman spectroscopy. Materials were prepared by wet-impregnation method and selective catalytic reduction (SCR) of NO was measured for materials studied. Raman spectra of catalysts as well as manganese oxides are presented. It was found that there is strong correlation of the position and the width of E2g mode of anatase at 146 cm-1 and Mn-oxide(s) concentration. The Mn/TiO2 samples show that this peak gradually decreases in intensity becomes broader and shifts to the high frequency region with increase of Mn loading and disappeared at the concentration of Mn-oxide above 11%. At low loading, Mn-oxide forms monolayer structures with Mn atoms incorporated to the crystalline lattice. At concentrations above 11%, Mn-oxide forms microcrystalline species. The position and broadening of the peak can be described by the optical confinement model that depends on the size of the nano-crystals. A strong correlation between the shape of E2g mode and catalytic activity was found.
D6: Materials for Energy Production and Storage
Session Chairs
Wednesday PM, November 30, 2011
Back Bay B (Sheraton)
11:30 AM - **D6.1
Low-Temperature Carbon Materials for Energy Storage Processes.
Robert Schloegl 1
1 Inorganic Chemistry, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Berlin, Germany
Show AbstractThe enhanced utilization of renewable energy with its main component of primary electricity calls for large-scale solution to store the energy for various time scales. Besides thermo mechanical solutions and batteries the conversion of electricity into chemical fuels is of relevance when no shadow fossil fuel solutions are availableElectrolysis of water is a scalable solution provided that we solve the challenges of excess overpotential, of using noble metal electrocatalysts and of limited stability during intermittent operation.The contribution lists some of the origins of these shortcomings using model experiments with Pt single crystals. Then we discuss the possibility to use carbon as electrode material without adding noble metals. We report on the combination of carbon nanotube supports with Mn-oxide nanoparticles as oxygen evolution electrodes and review the possibilities to generate carbon materials with suitable stability against oxygen attack. The strategy towards these materials starts from nitrogen-containing organic precursors and uses a combination of hydrothermal and medium-temperature thermal treatments to arrive at suitable carbon materials without going through graphitization steps. The possibility to use these novel carbon materials also in battery applications will be discussed.
12:00 PM - D6.2
Electrospinning Synthesis of LiFePO4 Nanowires and Corresponding Electrochemical Activity in Li-Ion Battery.
Junjie Niu 1 2 , Akihiro Kushima 1 2 , Liang Qi 1 2 , Jian Yu Huang 3 , Ju Li 1 2
1 Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States, 2 Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 3 Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractOne-dimensional LiFePO4 nanomaterials have the potential of fast charging, high power-density and high chemical stability, which are necessary for portable devices like laptop and cell phone. It has been shown that LiFePO4-C is an intrinsically safer cathode material than the commercial LiCoO2 and manganese spinel. However, as an olivine structure, lithium iron phosphate nanowires are difficult to form via regular physical or chemical method. In our previous work, we haved reported a nanoscale electrochemical device—consisting of a single tin dioxide nanowire anode, an ionic liquid electrolyte, and a bulk lithium cobalt dioxide cathode—and the in situ observation of the lithiation of the SnO2 nanowire during electrochemical charging using transmission electron microscope (TEM) (Jian Yu Huang et al. Science 330, 1515-1520 (2010)). In current work, large scales of LiFePO4 nanowires were synthesized using an electrospinning method. LiC2H3O2.2H2O, Fe(NO3)3.9H2O, H3PO4 and poly acrylic acid (MW:240000) were used as chemical reagents and a high voltage of 18-25 kV was applied to obtain the nanowires. A poly-crystal LiFePO4 with a small amount of carbon was received. The carbonated carbon inside assisted the formation of nanowires and also will improve the electrochemical performance. The treated nanowires were used for charging/discharging test under in-situ TEM. The lithiation/delithiation process along the nanowire was well analyzed.
12:15 PM - D6.3
Aluminum-Ion Batteries with Excellent Cycle Life and Improved Performance.
Jayaprakash Navaneedhakrishnan 1 , Lynden Archer 1
1 , Cornell University, Ithaca, New York, United States
Show AbstractWe have designed a novel Al-ion battery with excellent cycle life and improved capacity ever reported in the literature. The battery system works with an ionic liquid based electrolyte containing Al salt. When calculated, the battery delivered a discharge capacity more than 300 mAh/g, with a very stable cycle performance. Since the system exploits aluminum or aluminum intercalation/deintercalation compounds as electrodes, it has many advantages over the conventional Li-ion system. Also, Al-ion system has very high energy density and economically viable status due to the surplus availability of the metal. We have also studied the intercalation deintercalation behavior of various metal oxides against aluminum anode and derived a suitable metal oxide with enhanced electrochemical performance. Various reasons for the improved cycle life will be discussed in detail with experimental evidences.
12:30 PM - D6.4
Synthesis, Characterization, and Supercapacitor Application of RuO2 and Graphene-RuO2 Nanocomposite Materials.
Mohamad Khawaja 1 , Manoj Ram 2 3 , Farah Alvi 3 , Yogi Goswami 1 , Ashok Kumar 2 3 , Elias Stefanakos 1
1 Center for Clean Energy, University of South Flrodai, Tampa, Florida, United States, 2 Nanotechnology Education and Research Center, University of South Florida, Tampa, Florida, United States, 3 Mechanical Engineering, University of South Florida, Tampa, Florida, United States
Show AbstractElectrochemical supercapacitor has high energy density with an excellent reversibility, and is operated at greater specific power than most rechargeable batteries. Therefore, research has been focused on improving the novel materials and methods to enhance the operation of supercapacitors. Activated carbon metal oxides (ruthenium oxide ‘RuO2’, MnO2) take advantage over conducting polymers for their stability. Mixing conducting polymers and metal oxides has recently been investigated to understand the behavior and stability of the hybrid supercapacitor. This research project focuses on supercapacitor electrodes coated with RuO2 and graphene (G)-RuO2 synthesized materials.The G-RuO2 and RuO2 nanomaterials were synthesized using sol-gel technique. Besides, the commercially obtained ruthenium oxide was used for comparison purposes. The RuO2 and G-RuO2 materials were characterized using electrochemistry, Scanning Electron Microscopy (SEM), Raman spectroscopy, X-ray-diffraction, and Transmission Electron Microscopy (TEM) techniques. The synthesized G-RuO2 and RuO2 powder and the commercial RuO2 were mixed with Nafion and coated on graphite electrodes. The cyclic voltammogram, charging-discharging, stability, and life cycle of the various RuO2 and G-RuO2 materials were studied in supercapacitor configurations. This study provides a fundamental understanding for high performance synthesized RuO2 as well as G-RuO2 material. The high specific capacitance and stable charging –discharging cycles have been observed in G-RuO2 containing equal ratio of graphene to RuO2. This study provides a fundamental understanding of supercapacitor applications for high performance synthesized RuO2 and G-RuO2 nanoparticles. Based on experimental data shown in this work, we believe that G-RuO2 supercapacitor technology could be viable for commercial applications.
12:45 PM - D6.5
Influence of the Index Metallic Salts - Complexing Agent in a Sol-Gel Process to Obtain Nanoscaled Zirconium Substituted Yttrium (YSZ) to Electrolyte Application in Solid Oxide Fuel Cell (SOFC).
Rene Cienfuegos Pelaes 1 2 , Alejandro Ehecatl Correa Ceron 3 , Ramona Alicia Salazar de Leon 3 , Leonardo Chavez Guerrero 1 2 , Sugeheidy Carranza Bernal 1 , Moises Hinojosa Rivera 1 2
1 Materiales, Facultad de Ingenieria Mecanica Electrica, San Nicolas de los Garza, Nuevo Leon, Mexico, 2 Advanced Materials, Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología, Apodaca, Nuevo Leon, Mexico, 3 Ciencias químicas, Facultad de Ciencias Químicas, San Nicolas de los Garza, Nuevo Leon, Mexico
Show AbstractThe objective of the present study is to obtain the electrolyte material YSZ a low cost via sol gel through exploration of the index rate between the complexing agents and the metallic salts (HMTA / metallic salts) from 1 to 5 prepared by a polymeric way in a sol gel process. We show an easy method that could be used in the industrial scale in order to obtain solid electrolyte material for its application in SOFC to operate at temperatures in the range of 700 800°C. The zirconium substituted to 8% of yttrium (CYSZ= 0.2 mol*L-1 metallic salts concentration-) having as reference the papers from Lenormand and Rieu. The presence of the phase in the materials has been confirmed by X-ray diffraction assisted by thermal analysis tests , for indexes from 2 to 5 at a temperature of 1000°C for 5 hours at a calcination rate (from amorphous dust obtained at 400°C) of 1000°C per hour. The grain average size for crystalline powder has an average near 50 nm and standard deviation close to 9 nm, it was confirmed by scanning electron microscope (SEM).
D7: Sustainable and Energy-Efficient Synthesis I
Session Chairs
Wednesday PM, November 30, 2011
Back Bay B (Sheraton)
2:30 PM - **D7.1
Solution-Based Vapor Deposition of Green Materials: Oxides and Organic Thin Films and Nanomaterials.
Shizuo Fujita 1 , Kentaro Kaneko 1 2 , Takumi Ikenoue 1 2 , Hiroshi Ito 1 , Takuto Igawa 1 , Jinchun Piao 1 2 , Sam-Dong Lee 1 2 , Shigetaka Katori 2
1 Photonics and Electronics Science and Engineering Center , Kyoto University, Kyoto Japan, 2 Department of Electronic Science and Engineering, Kyoto University, Kyoto Japan
Show AbstractThe increasing needs for "green materials", that is, stable and environmental-friendly materials together with unique functions, have encouraged us to develop novel oxide and organic semiconducting thin films and nanomaterials. The progress of "green chemistry", with which we can reduce the energy required for materials fabrication is important for the enhanced propagation of new devices at low cost. Interestingly, oxide semiconductors can potentially be grown by non-vacuum-based simple technologies through "green chemistry", because oxygen is not an impurity and no maximum care to remove oxide impurities may be essential. For organic semiconductors, solution-based "green chemistry" such as ink-jet printing, spin-coating, and spray-coating has already been developed for certain materials, but a new technology has always been required for the effective use. The combination of "green materials" and "green chemistry" is an essential issue in order to support the environmental-friendly economical development in our planet.As an oxide semiconductor, focused researches have been carried out for ZnO. In addition, we pay attention to various oxides because oxide semiconductors possess a variety of functions. For the growth of oxide semiconductors through "green chemistry", we have developed the ultrasonic-spray mist chemical vapor deposition technique, where safe and inexpensive liquids are used as source and they are atomized by ultrasonic so that their mist particles are transferred by carrier gas into the heated reaction area. This has successfully been applied to amorphous, polycrystalline, and single-crystalline semiconductors. Increasing demands for ZnO transparent electrodes have been satisfied with this technique. Layer-by-layer growth of single-crystalline ZnO, together with its reasonable electrical properties, has also been succeeded. Recently, we showed the growth of corundum-structured Ga2O3 on sapphire substrate, followed by (GaFe)2O3 alloys exhibiting ferromagnetic properties, suggesting future application as spintronic materials. Other oxides investigated include SnO2, Cr2O3, V2O3, Fe3O4, and LiMn2O4.The mist-based deposition technology has also been applied to organic materials. We have showed the deposition of an electroluminescent material, aluminum tris(8-hydroxyquinoline) (Alq3), a conductive polymer, PEDOT:PSS, and so on. These materials have generally been deposited by vacuum evaporation or spin-coating, but with the mist-based technology we can eliminate the vacuum process (compared to vacuum evaporation), perform uniform deposition with precise thickness control (compared to spin-coating), and reduce the wastes of source materials. Applications to fabricate solar-cells and light-emitters are also in progress.
3:00 PM - D7.2
Sustainable Synthesis of Semiconductor Nanoparticles in a Continuous Flow Reactor.
Daniel Ness 1 2 , Jan Niehaus 1 , Huong Tran 2 , Horst Weller 1 2
1 , CAN Hamburg, Hamburg Germany, 2 Physical Chemistry, University of Hamburg, Hamburg Germany
Show AbstractMaterials in the nanoscale range have gained tremendous interest not only in research areas but also in industry over the past twenty years. Their special properties arising from size-dependent attributes and a great variety in material composition have shown to be valuable in a range of different applications.[1] Within this paper we present a system which is capable of the sustainable and continuous production of fluorescent nanoparticles (NP).
Cd-based fluorescent NPs – Quantum Dots (QDs) - in particular found a great acceptance in processes for monitoring and targeting, e.g. in light emitting devices or lasers[2] as well as marker for biological systems like proteins or DNA.[3] For this reason methods for protective coating of the more or less instable core (CdSe) have been developed leading to structures with CdS, ZnS or CdS/ZnS as shell components among others.[4]
Because of their widespread use in research as well as industry a sustainable synthetic method is essential to guarantee consistent properties over time without losing the ability to customize the particles as required. The common strategy for the synthesis of QDs is based on a batch process called hot-injection method.[5] This procedure requires high nucleation temperature, a fast cooling step to the growth temperature and immediate and complete mixing after the injection. Up-scaling the synthesis is difficult in this manner and leads to slightly different properties each time the reaction has been performed.
This issue can be addressed by performing the synthesis in a continuous flow reactor.[6] Combining the utilization needs with the features of such a technical system for the production of NPs gives some crucial advantages over the common batch synthesis:
- reaction conditions can simply be modified and adjusted
- easy optimization of particle systems by rapid screening of parameters
- avoiding wastage of expensive materials and time
- high reproducibility of NP properties
- online quality control by integrated spectroscopic units
- enhancement of production even to the kg-scale possible
The perceptions obtained from over 20 years of excessive research in the area of light-emitting NPs has been considered in the design of this system. Therefore it is possible to synthesize simple CdSe core particles as well as core-shell like structures.
[1] A. P. Alivisatos, Science 1996, 271, 933-937.
[2] R. Xie et al., J. Am. Chem. Soc. 2005, 127, 7480-7488.
[3] R. Jin, Angew. Chem. 2008, 180, 6852-6855.
[4] P. Reiss et al., Small 2009, 5, No. 2, 154–168.
[5] H. Weller et al., J. Phys. Chem. B 2003, 107, 7454-7462.
[6] B. K. H. Yen et al., Adv. Mater. 2003, 15, 1858-1862.
3:15 PM - D7.3
Sustainable Synthesis of Nanowires at Low-Temperature from Aqueous Solutions Driven by Screw Dislocations.
Fei Meng 1 , Linsen Li 1 , Salih Hacialioglu 1 , Song Jin 1
1 Chemistry, University of Wisconsin Madison, Madison, Wisconsin, United States
Show AbstractVapor-Liquid-Solid (VLS) growth and analogous catalyst-driven mechanisms almost exclusively explain modern nanowire (NW) growth. Such synthesis require catalysts which are usually noble metal nanoparticles, and are often conducted in high vacuum and high temperature environments that inevitably increase the cost and energy consumption of the NW production. We have recently reported a new catalyst-free and template-free NW growth mechanism in which axial screw dislocations provide self-perpetuating steps to enable one-dimensional crystal growth. This growth mechanism can be operated in either vapor or solution phase, the latter of which is intrinsically more scalable and less costly than the former. We have shown a variety of different materials such as zinc oxide (ZnO), iron oxides/hydroxides, cuprous oxide (Cu2O) and copper (Cu) can be synthesized into NW morphology in low-temperature aqueous solutions via this growth mechanism. The key to promote the dislocation-driven growth is maintaining a constant low precursor supersaturation, which is achieved using a continuous flow reactor (CFR). Furthermore, we design a close-loop CFR where the unreacted precursors can be recycled and reused to equilibrium concentration, therefore making the synthesis more cost- and chemical-efficient. We believe that the continuous solution synthesis may ultimately become the most inexpensive, chemical- and energy-efficient large-scale synthetic method for practically manufacturing NWs for large-scale applications.
3:30 PM - D7.4
Metal-Catalyzed, Energy-Efficient Growth of Crystalline Semiconductor Nanodots, Nanowires and Thin Films at Temperatures below 180°C.
Zumin Wang 1 , Lars Jeurgens 1 , Fritz Phillipp 1 , Eric Mittemeijer 1
1 , Max Planck Institute for Intelligent Systems, Stuttgart Germany
Show AbstractCrystalline semiconductor nanostructures, such as zero-dimensional nanodots, one-dimensional nanowires and two-dimensional nanolayers, have attracted tremendous interest in recent years, due to their numerous potential applications, for example, in nanoelectronics, flexible electronics, photonics, sensors, and in energy harvesting and storage devices. Yet the application of semiconductor nanostructures on a large, industrial scale is hampered by their high fabrication costs, which is primarily due to the required high processing temperatures (500-1200°C) and/or the use of expensive catalysts, such as gold and silver. Advanced by the recently reached fundamental understanding of the metal-induced crystallization (MIC) of amorphous semiconductors [1, 2], an innovative set of routes for fabrication of various crystalline semiconductor nanostructures (nanodots, nanowires [3], nanolayers) have now been developed, which enable strikingly low growth temperatures (lower than 180 °C) and the use of cheap catalysts, like aluminium. The method can easily be scaled up to the industrial scale and also allows the direct fabrication of semiconductor-nanostructure-based devices on low-cost, but heat-sensitive, flexible substrates.[1] Z.M. Wang, J.Y. Wang, L.P.H. Jeurgens and E.J. Mittemeijer, Phys. Rev. Lett. 100 (2008) 125503. [2] Z.M. Wang, J.Y. Wang, L.P.H. Jeurgens and E.J. Mittemeijer, Phys. Rev. B 77 (2008) 045424.[3] Z.M. Wang, L. Gu, F. Phillipp, J.Y. Wang, L.P.H. Jeurgens and E.J. Mittemeijer, Adv. Mater. 23 (2011) 854.
3:45 PM - D7.5
Energy-Efficient Synthesis of Ferrite Powders and Films.
Ranajit Sai 1 2 , Suresh Kulkarni 1 2 , Navakanta Bhat 2 3 , Srinivasrao Shivashankar 1 2
1 Materials Research Centre, Indian Institute of Science, Bangalore, Karnataka, India, 2 Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 3 Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore, Karnataka, India
Show AbstractIn recent years, there has been significant effort in the synthesis of nanocrystalline spinel ferrites due to their unique properties. Among them, zinc ferrite has been widely investigated for countless applications. Many methods already explored for the synthesis of polycrystalline ferrites include ball milling and solid state reactions, each typically taking several hours of processing time, followed by annealing at high temperatures for hours. These steps constitute high overall energy requirement for the process and are contrary to modern industrial and environmental requirements. Solution-based synthesis routes offer relatively quick processes, but hours of annealing at elevated temperature is still unavoidable. Thus, there is need for a resource-effective process that can prepare ferrites quickly and efficiently without compromising material quality. In the present work, a novel microwave-assisted soft-chemical synthesis technique in the liquid medium has been developed for synthesis of ZnFe2O4 powder below 100°C, within 5 min. Instead of metal nitrates and chlorides, non-hazardous and easily soluble metal complexes (typically β-diketonates, in 1:2 molar proportion for Zn:Fe) featuring direct metal-to-oxygen bonds in their molecular structure were chosen as the precursors, not only to reduce the solution preparation time and overall process temperature, but also to end up with only water-soluble and non-toxic by-products. All solvents and ingredients were chosen carefully, to reduce the mixing time and to address related environmental issues. The solution then is subjected to irradiation in a microwave oven (2.45 GHz) for 5 minutes. The entire process, including solution preparation and centrifugation, requires < 30 min. As synthesized powder then annealed at 300oC for 2 hour in a conventional anneal (CA) schedule. Calculations show that 2 hour annealing takes ~15 times the energy as the rest of the process. To minimize this, a 2-min rapid anneal at 300oC (RA) is developed and shown to be sufficient to crystallize the ferrite particles, which show a saturation magnetization (MS) of 38 emu/g, compared with 39 emu/g for a 2-hr CA. This signifies that our process is efficient enough to reduce energy consumption by ~90% just by altering the anneal scheme. Recognising the criticality of anneal process to the energy budget, a more energy-efficient variation of the process was developed. By exposing the mother solution to single mode microwave radiation (2.45 GHz) in a closed chamber, operating pressure can be raised, which raises the reaction temperature without adding to the energy bill. The resulting powder is already nanocrystalline and ferrimagnetic zinc ferrite, eliminating the need for power-hungry annealing. Thus, present work offers a resource-effective and energy- efficient way of processing functional oxide ceramics. It will be shown that the process also can be employed to deposit crystalline thin films of ferrites.
D8: Sustainable and Energy-Efficient Synthesis II
Session Chairs
Wednesday PM, November 30, 2011
Back Bay B (Sheraton)
4:30 PM - **D8.1
Surface Engineering of Sustainable Cellulosic Materials by Atomic Layer Deposition.
Gregory Parsons 1
1 Chemical and Biomolecular Engineering, NC State University, Raleigh, North Carolina, United States
Show AbstractResearchers are looking to renewable and sustainable material resources and processes to fulfill product needs currently supplied by petrochemical-based polymers. New sustainable high surface area porous and materials, including spun, woven textiles and nonwoven fibrous mats can be used for separations, purification, and filtration, as well as supports for catalysis, electrochemical electrodes in fuel cells and renewable energy devices. However, sustainable fibrous materials require specific processing to achieve desired function. Chemical surface finishes for textiles and nonwovens are well known, but they mostly rely on energy intensive wet processing and drying. New low-energy routes to add high performance functionality into low cost renewable materials could have significant impact. Our group explores vapor phase surface reactions, including atomic layer deposition, molecular layer deposition and sequential vapor infiltration to achieve highly uniform surface modification and conformal thin film coatings on surfaces, including fibrous polymer substrates. To obtain high throughput, our studies include extending ALD to atmospheric pressure conditions at low temperature. As substrates, renewable cotton cellulose, paper, and other related materials are particularly interesting. Not only are these materials a sustainable resource that could simplify recovery and end-of-use reclamation, but their innate surface chemistry permits facile covalent reaction, and they have potential for interesting new device designs and function. For example, we find for woven cotton cellulose that ALD precursors readily penetrate into the woven fabric matrix and adsorb uniformly on the fiber surface to alter surface wetting, thereby adjusting functionality and subsequent reactivity. Likewise, conductive metal coatings by ALD on flexible and porous fiber structures, including cellulose paper, allow electronic integration and sensor fabrication. We also find that coatings are not limited to solid dense films. By coupling metalorganic and organic precursors in a molecular layer deposition sequence, we can coat a fiber mat with a uniform conformal organic-inorganic hybrid film and, with subsequent processing, transform that coating into a highly porous inorganic matrix with controlled pore size and pore size distribution. Possible impact of these processes on future applications of sustainable materials will be discussed.
5:00 PM - D8.2
Ultrafast and Energy-Efficient Microwave Processing of Lithium Nitride Nanowires.
Nuria Tapia-Ruiz 1 , Gregory Martin 2 , Ian MacLaren 3 , Jeremy Titman 2 , Duncan Gregory 1
1 Chemistry, University of Glasgow, Glasgow United Kingdom, 2 Chemistry, University of Nottingham, Nottingham United Kingdom, 3 Physics and Astronomy, University of Glasgow, Glasgow United Kingdom
Show AbstractLithium nitride and its derivatives offer a great number of potential applications such as battery components and hydrogen storage devices [1]. Recently, we established the existence of lithium nitride 1D and 2D nanostructures that could be synthesized apparently via a vapour mediated growth process [2]. These materials have shown improved properties and performance c.f. bulk lithium nitride. Amongst others, increased rates in hydrogen uptake and a reduction in the activation energy for lithium ion diffusion have been observed. This synthesis, however, requires relatively high temperatures, long reaction times and specific conditions, making the process challenging to scale up for future use in industry. In this work we report a novel, facile and energy-efficient method for the growth of lithium nitride nanostructured materials using microwave (MW) irradiation. Li3N as a fast ion conductor [3] is an excellent MW susceptor. The reaction is thought to proceed following a VLS mechanism where the incorporation of various precious metals e.g. Ag, Au and Pd is essential for the growth of 1D Li3N nanostructures. Processing times were reduced by an order of 103 over our previous growth method.Scanning electron microscopy/energy dispersive analysis by X-rays (SEM/EDX) and transmission electron microscopy/selected area electron diffraction (TEM/SAED) revealed lithium nitride consisting mainly of wires ranging from 100 nm to 1 μm in diameter with typical aspect ratios of up to ca. 500. TEM/SAED specifically allowed us to develop an understanding of the growth mechanism of these materials. The catalysts used for the growth of these nanostructures were chosen judiciously by considering their ability to form the corresponding lithium-metal alloys at relatively low temperatures [4] while being apparently inert to ternary nitride growth (no stable Li-Ag-N, Li-Au-N, Li-Pd-N nitrides are yet reported to exist). After the growth, several techniques were used in order to fully characterize these NWs. Powder X-ray diffraction and Raman spectroscopy were used initially to determine the phase composition of these samples. Scanning electron micrographs provide evidence of alloy catalysts at the tip of the nanowires, supporting the premise of a tip-growth mechanism by analogy to 1D carbonaceous nanostructure formation. SAED investigations revealed growth with the [001] direction perpendicular to the long axis of the wire i.e. with Li and [Li2N] layers parallel to the wire long axis. 7Li NMR spectra of the NWs evidenced the presence of two Li sites with quadrupolar constants of 283 KHZ and 578 KHz corresponding to the intraplanar and interplanar lithium positions in the Li3N structure.[1] D.H. Gregory, Chem.Rec., 2008, 8(4), 229-39; [2] D.H. Gregory, A.G. Gordon, International Patent WO 2004057070 A2, 2004 [3] B.A. Boukamp, R.A. Huggins, Phys.Lett., 1976, A58, 231; [4] A.D. Pelton, J.Phase Equilib., 7, 3, 223-228.
5:15 PM - D8.3
Microwave-Solvothermal Synthesis for Rapid and Scalable Production of Tunably Doped Nanocrystals and Their Assemblies.
Rutvik Mehta 1 , Yanliang Zhang 2 , Priyanka Jood 1 , Nikhil Balachander 1 , Richard Siegel 1 , Theodorian Borca-Tasciuc 2 , Ganpati Ramanath 1
1 Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 2 Mechanical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States
Show AbstractScalable and cost-effective production of nanocrystals with control over structure, shape, chemistry and doping, and hence properties, by eco-sensitive bottom-up methods is key to harnessing nanotechnology for many applications including energy, catalysis and healthcare. Here, we report a novel wet-chemistry technique using inexpensive organic solvents and non-toxic metal salts as reactants to rapidly sculpt metal, semiconductor, and oxide nanocrystals of controllable shapes, sizes and doping by microwave-stimulated surfactant-mediated non-aqueous solvothermal synthesis. Our synthesis in recyclable high-boiling polar solvents allows multi-gram-per-minute synthesis with nearly 100% yields of nanocrystal powders for realizing thin-film and bulk nanostructured solids through further nanocrystal assembly and processing. Organic surfactants are used in our synthesis for serving multiple roles of shape-direction, surface-passivation and oxide-inhibition and doping agents. Our method is versatile, and can be used for the synthesis of a wide variety of materials through the selection of appropriate precursor-surfactant molecule combinations. We will describe the salient features of our method through illustrative examples of synthesis of nanoparticles, nanoplates, and nanowires of sulfur-doped pnictogen chalcogenides, aluminum-, bismuth-, indium-doped zinc oxide, and metal nanostructures such as gold, bismuth and antimony. We will show that our method can be used for morphing and heterostructuring the nanocrystals that allow control over properties such as Seebeck coefficient, and lead to up to billion-fold enhancement in electrical conductivity. We conclude with examples of how bulk nanostructured pnictogen chalcogenides and oxides obtained by our method exhibit large enhancements in thermoelectric figure-of-merit.
5:30 PM - D8.4
Thermal Decomposition of Hydroxystannate Cubes into Stannate-Based Semiconductor Nanocomposites for Energy Harvesting and Utilization.
Caihong Liu 1 , Gregory Wrobel 1 , Pu-Xian Gao 1
1 The Institute of Materials Science, University of Connecticut, Storrs, Connecticut, United States
Show AbstractTernary metal oxides constitute an important category of functional materials, typically including ABO3 type perovksites and A2BO4 spinels. Zinc hydroxystannate (ZHS) thermal decomposition products including amorphous and crystalline ZnSnO3, spinel Zn2SnO4, and crystalline ZnO, SnO2 have been reported to be used in lithium ion battery anodes, transparent semiconductor electrodes, solar cell anodes, and gas/vapor sensors. However, this versatile Sn-based ternary oxides system is yet to be closely examined at the nanoscale. Herein, we prepared template structure zinc hydroxystannate (ZnSn(OH)6) micro- and nano-cube films hydrothermally. We then applied a thermal treatment engineer zinc stannate (ZnSnO3), spinel zinc stannate (Zn2SnO4). The structure evolution upon thermal annealing of ZHS cubes at different temperatures and in varying atmospheres have been investigated to understand the thermodynamics and kinetics behind the nanostructure phase conversion processes. The electronic and optical properties evolution in the ZHS cubes, and thermally engineered products, i.e. ZnSnO3, spinel Zn2SnO4 microcubes also have been explored for their potential application in solar energy
[email protected]5:45 PM - D8.5
Direct Preparation of Platinum Nanoparticle Dispersion from Platinum Bulk Metal and Platinum Ions Using a Microwave-Induced Plasma in Liquid.
Tetsu Yonezawa 1 , Shota Arai 1 , Hiroyuki Takahashi 1 , Takashi Narushima 1
1 Materials Science, Hokkaido University, Sapporo Japan
Show AbstractA basic study of microwave induced plasma in liquid at atmospheric pressure for rapid and mass production of platinum nanoparticles was conducted. We have successfully prepared platinum nanoparticles directly from bulk platinum rods as well as platinum ions by using microwave induced plasma in water. Usually, in order to obtain continuous discharges by pulsed high voltage for example, control of electro conductivity of the reaction solution is required. However, as microwave was chosen as the plasma energy in our equipment, no optimization of electro conductivity was demanded. As the metal sauce, we have chosen a platinum rod according to the relatively low price and a water-soluble platinum ion for preparing a uniform reaction solution. When the platinum ion was used as a precursor of platinum nanoparticles, tungsten electrodes were used for plasma irradiation. By igniting plasma on the top of the electrode (platinum or tungsten) and the ring GND electrode (tungsten), black or blown platinum nanoparticles were generated into water immediately. The particles formed in the plasma immediately cooled down in water and disperse stably for some months with and even without addition of any stabilizing reagents. No aggregation or precipitation of particles was observed in all cases. It is probably due to the hydroxyl radicals generated by plasma in water these nanoparticles were stably dispersed even without a stabilizing reagent for months. OH- ions coated the particle surfaces to prevent their coagulation. No reducing reagent was needed to form metallic platinum. In some cases, addition of stabilizing polymers introduced aggregation of the nanoparticles. TEM revealed that the obtained particle size was ca. 1 - 2 nm, which is quite useful as catalysts for fuel cells as well as organic reactions, and that they were quite uniform. Dispersing of carbon black in water during the plasma irradiation, carbon-supported platinum catalysts could also be obtained. These catalysts could work effectively for fuel cells. We emphasize this process can be a good candidate for suitable synthesis of platinum catalysts. This direct plasma preparation process of metal nanoparticles is also applied to other precious metals, such as gold, silver, palladium and so on.
D9: Poster Session: Sustainable Synthesis, Characterization, and Application
Session Chairs
Mato Knez
Woo Lee
Stanislaus Wong
Thursday AM, December 01, 2011
Exhibition Hall C (Hynes)
9:00 PM - D9.1
Synthesis of Nanocrystalline Alumina Powders with Seeding by Egg White Solution Route.
Adriana Chinelatto 1 , Raphael Salem 1 , Keterine Guilherme 1 , Adilson Chinelatto 1
1 Materials Engineering, Ponta Grossa State University, Ponta Grossa, PR, Brazil
Show AbstractAlumina ceramics are used in many areas of modern industry because of their excellent mechanical, thermal and optical properties. Synthesis of α-alumina powders is normally accompanied by an inherent growth of crystals during the calcination process, since this phase forms at temperatures above 1200°C. Many studies have been done trying to reduce the formation temperature of α-alumina, intending to obtain a stable powder with finer granulometry. Due to its solubility in water, egg white has been used as gelling agent in chemical synthesis of various ceramic powders, leading to obtain of nanocrystalline particles at relatively low temperatures. It is possible through the entrapment of metallic ions in the matrix formed by protein molecules present in egg white. This method constitutes a promising synthesis route of preparation of ultrafine alumina powders, in a relatively economic and environmental friendly way. In this work it was studied the synthesis of alumina particles through this method, with addition of seeds of calcined α-alumina. An aqueous solution of aluminum nitrate nonahydrate was mixed with fresh egg white and 10 wt.% of seeds at 80°C until gelling. The precursors were pre-calcined at 500°C in order to eliminate organics and the resulting powder was calcined at the temperatures of 900, 1000 and 1100°C. The precursor was characterized by differential thermal analysis and thermogravimetry, and the powder was characterized by X-ray diffraction, specific surface area measurements, infrared spectroscopy, differential thermal analysis, thermogravimetry and scanning electron microscopy. It was verified that egg white route with seeding was effective to obtain high-purity α-alumina particles in the form of soft agglomerates, at lower temperatures than non-seeded powders.
9:00 PM - D9.10
Fabrication of Nanosheet-Layered Silicate Thin Films with Atomically Patterned Topmost Surfaces Using the Natural Mica Mineral for Exploration of Intercalation-Induced Functionalities.
Geng Tan 1 , Hirokazu Nakai 1 , Yumiko Miyake 1 , Ryosuke Yamauchi 1 , Mamoru Yoshimoto 1
1 Innovative & Engineered Materials, Tokyo Institute of Technology, Yokohama Japan
Show AbstractSo far, atomically layered compounds such as metal dichalcogenides, graphite intercalation compounds, and high-Tc superconducting cuprates have been extensively investigated, owing to their novel electronic properties, quasi-two-dimensional physics, and material anisotropy. Among the layered minerals, mica is a well-known silicate compound. Natural or synthetic mica powders has been used for many years in industry as an insulating material, a composite with glass, a heat-resistant material, a condenser, and among others. Typical mica minerals are muscovite (K2Al4(Al2Si6O20)(OH)4) and biotite (K2(Mg,Fe)6(Al2Si6O20)(OH)4). Mica can be easily cleaved in a specific manner because of this distinctive structure. Because natural biotite is trioctahedrally coordinated with six Mg2+ and Fe2+ cations occupying the octahedral sites, its magnetic and electrical conduction properties depend strongly on the concentration of Fe ions. For industrial applications, most synthetic mica has been produced in bulk or powder form by a melting method. However, there are few reports on fabrication of mica thin films via vapor phase processes. Synthesis of mica thin films is expected to open new possibilities for electronic devices because of the layer structure and the flat surface with an atomic-scale pattern. Pulsed laser deposition (PLD) process used in this work yields high-quality multi-component crystalline thin films with compositions comparable to that of the target. In this study, we report the first successful fabrication of a c-axis oriented biotite-mica thin film by PLD using a sintered target consisting of natural biotite powders. Synthesis of crystalline biotite-mica thin films was examined by applying a two-step process: (1) low-temperature growth of the mica film precursor on an ultrasmooth sapphire (α-Al2O3 single crystal) substrate by pulsed laser deposition using a sintered biotite ceramics target and (2) post-annealing in vacuum. X-ray diffraction and Raman scattering spectroscopy confirmed that a c-axis-oriented polycrystalline biotite-mica thin film was obtained by post-annealing the 500C-grown film precursor at temperatures above 700C in vacuum. An atomic-scale pattern corresponding to that of the cleaved natural mica surface was observed on the surface of thin film by atomic force spectroscopy.
9:00 PM - D9.11
Oxidation-Stable Cu0 and In0 Nanoparticles.
Christian Kind 1 , Claus Feldmann 1
1 Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe Germany
Show AbstractThe synthesis of nanoscaled metals typically becomes the more elaborate the lower the relevant electrochemical potential is. This is due to the high reactivity of less-noble metals (e.g. In, Sn, Bi, Pb), for instance, toward moisture and oxygen. However, even comparable noble metals (e.g. Cu) become high-reactive with diameters on the nanoscale. With regard to application the availability of sufficient quantities of less-noble metal nanoparticles is still a primal challenge [1]. Cu0 nanoparticles are highly relevant to thin-film electronics and sensors, high-power batteries or solar cells. In0 is interesting in view of its quantum-size effects, melting behavior, as well as a pure element source in view of a range of chemical conversions, e.g., to InN, InP, InAs, In2O3, In2S3 or In2Se3. As a nanomaterial all these compounds are highly requested for light emitting diodes, transparent conductive oxides, solar cells or catalysis.In this study, we present a size-selective synthesis giving access even to less-noble metal nanoparticles [2]. The synthesis is based on a modified polyol method, including the use of low-molecular citrate as an easily decomposable, reductive capping agent. The use of long-chained molecules and high-molecular-weight polymers – that are normally difficult to remove – is avoided. The versatility of the approach is demonstrated by the synthesis of oxidation-stable Cu0 and In0 nanoparticles. The nanomaterials are characterized by various analytical tools, for instance, electron microscopy, dynamic light scattering, X-ray powder diffraction, UV-Vis, and FT-IR spectroscopy.Cu0 nanoparticles, 20 nm in diameter and with narrow size distribution are obtained by the reduction of intermediate copper citrate nanoparticles. The as-prepared and citrate-capped Cu0 nanoparticles turn out as stable against air oxidation for several months. Via simple drop-coating, porous Cu0 thin-films are prepared on glass substrates that exhibit bulk-like sheet resistances of 0.32 Ω■ after sintering at 250 °C (bulk-Cu sheets under similar conditions with 0.30 Ω■) [3].In addition, a facile one-pot synthesis of almost monodisperse In0 nanoparticles based on common InCl3x4H2O as a starting material is presented. The particle size can be adjusted in a range of 8–100 nm. Due to the citrate capping, suspensions and powders can be stored for weeks in contact to air, without oxidation or sedimentation. The smallest, 8 nm-sized In0 particles, finally, turn out as molten at room temperature [4].References:[1] H. Goesmann, C. Feldmann, Angew. Chem. Int. Ed. 2010, 49, 1362.[2] C. Kind, C. Feldmann, F. Rauscher, H. Lu, K. Köhler, L. Mleczko, EP 11165705.2, 2011.[3] C. Kind, C. Feldmann, 2011, submitted. [4] C. Kind, C. Feldmann, 2011, submitted.
9:00 PM - D9.15
Nanostructured Hybrid Bifunctional Magnetic-Luminescent Materials Based on Magnetite and Semiconducting Polymer.
Paola Gomez 1 , Virgilio Gonzalez 1 , Marco Garza 1 , Reynaldo Esquivel 1
1 Departamento de Posgrado de la Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, Mexico
Show AbstractIn this contribution, the synthesis and characterization of new bifunctional magnetic-luminescent hybrid nanostructured materials (BHNM's) based on the semiconducting polymer poly-(4-methyl-1-fenylpenta-1,4-dien-ona) (PMFDO) and magnetite nanoparticles (MNPS) is reported. Bifunctional hybrid nanostructured materials were synthesized following an in situ precipitation procedure, departing from inorganic salts dissolved into the PMFDO matrix, and using aqueous sodium hydroxide (NaOH) dissolution as precipitant reagent. This procedure was performed using the necessary proportions of FeCl2-4H2O, FeCl3-6H2O, PMFDO and NaOH to obtain BHNM's at PMFDO: MNPS weight content ratios of 75:25 and 85:15 %wt. The resultant BHNM's were studied by techniques such as high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), fourier transform infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV-vis), fluorescence spectroscopy (FSPC) and static magnetic measurements (SMM). The results obtained from these techniques suggest that following the proposed synthetic procedure it is possible to obtain BHNM's based on PMFDO and MNPS, which display remarkable narrow particle size distributions, with a mean diameter of 4.8 nm. Furthermore, it was observed that these narrow particle size distributions could be related to the steric stabilization given by the PMFDO macromolecules, which seems to be adsorbed onto particles surface. This kind of interaction induces noticeable changes on the semiconducting properties of BHNM's with respect those observed from PMFDO matrix. Moreover, due to this stabilization feature, it was also observed that static magnetic properties of the MNPS depict a remarkable temperature dependence, which can be attributed to single-domain magnetic arrangement.
9:00 PM - D9.16
Scale-up Synthesis of Nanostructured Copper Hydroxystannates and Cu-Sn Dendrites on Selected Substrates.
Kuo-ting Liao 1 , Paresh Shimpi 1 , Puxian Gao 1
1 Chemical,Materials & Biomolecular Engineering and Institute of Material Science, UConn, Storrs, Connecticut, United States
Show AbstractLarge scale free standing copper hydroxystannate nanocubes and Cu-Sn nanodendrites alloy have been successfully synthesized by simple and low cost low temperature wet-chemical method. By varying different Cu and Sn ion ratio in growth precursor solution with different solid substrates, different fractions and morphologies can be achieved. The structure, morphology and chemical properties of synthesized copper hydroxystannate and Cu–Sn nanodendrite alloy by X-ray diffraction analysis, electron microscopy, and various spectroscopies. The thermal decomposition process of copper hydroxystannates have also been investigated by using differential scanning calorimetry (DSC) and thermo-gravometric analysis (TGA). The possible growth mechanism has been proposed for these nanostructures. The decomposed hydroxystannate cubes and the dendrite like Cu-Sn nanostructured alloy could be good candidates for Li ion battery and lead free solder. *
[email protected]9:00 PM - D9.17
First-Principles Calculations of CO Oxidation on Gold Surfaces.
Kazuyuki Okazaki-Maeda 1 2 , Mitsutaka Okumura 1 2
1 Dept. Chemistry, Osaka University, Toyonaka Japan, 2 CREST, Japan Science and Technology Agency, Kawaguchi Japan
Show AbstractGold nano-particles supported on oxide, such as TiO2, exhibit high-catalytic activity for low-temperature CO oxidation [1], while bulk gold exhibits very low catalytic activity for oxidation generally [2]. It was proposed that the catalytic activity is originated from quantum size effects of Au nano-particles, from low-coordinated Au atoms of Au nano-particles, from perimeter regions at the contact of Au nano-particles on oxide surfaces, or the interaction between Au nano-particles and oxide supports. However, it is also important to investigate the interaction between reactants already adsorbed on Au surfaces in order to understand the reaction mechanism of CO oxidation on the Au catalysts. We treated not only CO and O but also CO and OH as reactants, because it was reported that hydroxyl groups attack CO on Au/oxide catalysts [3,4]. Therefore, we examine the coadsorption energies and configurations of CO with O or OH on Au surfaces using first-principles calculations based on density functional theory. The each coverage of CO, O, and OH is 0.125 ML.For Au(100) surface, an O atom is stably adsorbed on the 3-Hollow site surrounded by three Au atoms via the surface reconstruction and a OH species is stably adsorbed on the Bridge site between two Au atoms. For Au(111) surface, both an O atom and a OH species are stably adsorbed on the fcc-Hollow site. For coadsorption of CO with O on both the Au(100) and (111) surfaces, the electrostatics repulsive force acts between adsorbed CO and O. Therefore, CO2 can not be stably adsorbed on Au surfaces and the direct oxidation of CO does not occur on Au surfaces. On the other hands, the attractive force acts between CO and OH on both the Au(100) and (111) surfaces and a COOH species is naturally formed on the Au surfaces as the most stable configuration. This indicates the possibility that the formation of COOH is a key process in CO oxidation on Au catalysts.[1] M. Haruta, N. Yamada, T. Kobayashi, and S. Iijima, J. Catal., 115, 301 (1989). [2] B. Hammer and J. K. Nørskov, Nature, 376, 238 (1995). [3] G. C. Bond and D. T. Thompson, Gold Bull., 33, 41 (2000). [4] K. Qian, W. Zhang, H. Sun, J. Fang, B. He, Y. Ma, Z. Jiang, S. Wei, J. Yang, and W. Huang, J. Catal., 277, 95 (2011).
9:00 PM - D9.18
Mechanism of Microwave-Assisted Synthesis of Metal Catalysts on Oxide Supports and Activity for Catalytic H2 Combustion.
E. Anumol 1 , Paromita Kundu 1 , Parag Deshpande 2 , Giridhar Madras 2 , N. Ravishankar 1
1 Materials Research Centre, Indian Institute of Science, Bangalore India, 2 Department of Chemical Engineering, Indian Institute of Science, Bangalore India
Show AbstractMicrowave synthesis is increasingly used in the synthesis of nanomaterials owing to the fast kinetics, energy efficiency and special microwave effects. The special effects of microwave heating include superheating of solvents, volumetric heating, formation of hot spots and selective heating. Here we adopt a microwave assisted synthesis for obtaining metal nanoparticle decorated oxide materials making use of the selective heating of a dielectric substrate in a solvent resulting in heterogeneous nucleation of metal nanoparticles on the support. In the presence of an oxide support with high tanδ metal particles preferably nucleates on the substrate as the temperature for heterogeneous nucleation is readily achieved by the substrate before the solvent gets heated to the homogeneous nucleation temperature. The hybrid nanostructures obtained had a uniform distribution of metal particles on the oxide supports used. Thus a novel method is presented for the synthesis of supported metal catalyst along with strategies for controlling the particle size of the metal and the mechanism of formation of the metal nanoparticles on the oxide support in the microwave field. The synthesized Pt nanoparticle decorated CeO2 and TiO2 is shown to be a good catalyst material for H2 combustion showing 100% conversion at 50 degree Celsius and room temperature respectively.
9:00 PM - D9.19
Liquid/Gas Hybrid Atomic Layer Deposition of Titanium Oxide Thin Films.
Won-Sub Kwack 1 , Seung-Il Kim 2 , Seong-Ho Jeong 2 , Se-Hun Kwon 1
1 National Core Research Center for Hybrid Materials Solution, Pusan National University, Pusan Korea (the Republic of), 2 School of Materials Science and Engineering, Pusan National University, Pusan Korea (the Republic of)
Show AbstractAtomic layer deposition (ALD) has evaluated as an important thin film deposition technique for a variety of applications owing to its inherent abilities such as a digital controllability of sub-atomic level thickness, large area capability, excellent conformality, good reproducibility, simplification of the use of solid precursors, a wide range of film materials, high density, and low impurity level. In spite of its outstanding benefits, however, the major drawbacks of ALD technique are slow growth rate, high cost vacuum process, and the waste of precursors in ALD processes, which make it hard to be adopted in most industries. Hence, a novel method that can solve these drawbacks of conventional ALD process while keeping the inherent advantages of conventional ALD needs to be developed for being widely utilized in various industries.In this study, we proposed a novel liquid/gas hybrid ALD process to solve the drawbacks of conventional vacuum ALD. The liquid/gas hybrid ALD process had the advantages of wet-process such as low production cost and high deposition rate as well as the advantages of conventional vacuum based ALD such as excellent controllability of thickness, and good step coverage. In addition, we prepared TiO2 thin films by liquid/gas hybrid ALD process and conventional ALD respectively. In order to compare the growth characteristics and film properties of the TiO2 thin films, phase analysis was performed using X-ray diffraction(XRD), and the surface morphology was studied using field-emission scanning electron microscopy(FESEM) and atomic force microscopy(AFM). Finally, quantitative analysis was performed using auger electron spectroscopy(AES).
9:00 PM - D9.20
Rapid Synthesis of Polyhedral CeO2/Noble Metal Catalysts: Influence of Reactive Facets and Flow Rates on CO Conversion.
Nisha Singhania 1 , E. Anumol 1 , Giridhar Madras 2 , N. Ravishankar 1
1 Materials Research Centre, Indian Institute of Science, Bangalore India, 2 Department of Chemical Engineering, Indian Institute of Science, Bangalore India
Show AbstractCeria has attracted great attention due various applications in conversion catalysis, fuel cells, solar cells, gates for metal oxide semiconductor devices. Experimental and theoretical studies have shown surface and structure-dependent reactivity of ceria nanocrystallites. Here, we synthesize CeO2 nanocubes and nanooctahedra with dominant (100) and (111) reactive surfaces respectively. The size of these nanostructures is within the range of 30-40 nm. Catalytic activity studies with these nanostructures reveal the influence of the facets on the catalytic activity. We adopt an ultrafast, microwave-assisted route to attach capping-free, ultrafine noble metals such as gold and platinum on the ceria polyhedra. Under the same synthesis conditions, the size of the nanoparticles on different facets is different clearly revealing the difference in the efficacy for promoting heterogeneous nucleation. These heterojunction based nanostructures are found to be promising catalysts for CO oxidation and hydrogen combustion even at low temperatures. We have studied in detail the role of process parameters, particle size and the surface oxygen reducibility of ceria on the catalytic activity. The conversion rate varies with the different flow rates, different loading of catalysts, and different metal loading in the catalyst. Detailed structural characterization of these nanostructures were carried out using X-Ray Diffraction (XRD), X-Ray Photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), BET specific surface area analysis while temperature-programmed reduction (TPR) was used to study the influence of gold and platinum on ceria reducibility.
9:00 PM - D9.21
Rapid Synthesis of Surfactant-Free Ultrafine Noble Metal Nanocatalyst on Graphene: Synergistic Co-Reduction Mechanism and High Catalytic Activity.
Paromita Kundu 1 , C. Nethravathi 1 , Parag Deshpande 2 , Michael Rajamathi 3 , Giridhar Madras 2 , N. Ravishankar 1
1 Materials Research Centre, Indian Institute of Science, Bangalore India, 2 Department of Chemical Engineering, Indian Institute of Science, Bangalore India, 3 Department of Chemistry, St. Joseph's College, Bangalore India
Show AbstractGraphene, a monolayer of C atoms, is a fascinating material owing to its unique physical, chemical and electronic properties. High mechanical strength, thermal conductivity, specific surface area, transport properties have made it a reliable carbon based support system for Pd, Au and Pt nanoparticles in various applications viz. nanocatalyst for hydrogen storage, methanol oxidation for fuel cell and nanoelectronics. In case of catalysis, efficiency of the catalyst nanoparticles depends on the nature of the support and the catalyst/support interface in addition to the dispersion, size, shape and stability of the catalyst. However, the method of synthesizing these hybrids remains a challenge in terms of controlling the particle size, distribution of the noble metals nanoparticles on the graphene sheets and the stability of the catalyst under different conditions. Typical approaches for producing supported catalysts involve synthesis of catalyst particles employing surfactants to control particle size and their subsequent dispersion on the supports. We demonstrate a simple wet chemical route for rapid synthesis of graphene-based Pt nanoparticle hybrids. The method involves ethylene glycol as the solvent and reducing agent and a synergistic co-reduction mechanism describes the formation of the hybrid whereby the presence of the Pt ions leads to a faster reduction of GO and the the heterogeneous nucleation of Pt is facilitated owing to the presence of the defect sites on the reduced GO. Morphological characterisation and mechanistic investigation has been carried out using high resolution transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR) and x-ray diffraction (XRD). The resulting hybrid consists of ultrafine nanoparticles of Pt uniformly distributed on the reduced GO susbtrate. The electrocatalytic activity has been investigated for methanol oxidation using cyclic voltammetry which shows that these composites have exceptional activity for methanol oxidation with good long term stability. Besides, the hydrogen conversion efficiency of the catalyst is found to be excellent at room temperature conditions making it an ideal multifunctional hybrid based on graphene. The method anables excellent control over particle size and distribution on the support without the aid of functionalization and surfactant. Our approach is general and can be applied for other graphene-metal composite systems for a variety of applications.
9:00 PM - D9.22
Facile Assembly of Small EuS Nanocrystals.
Weidong He 1
1 , Vanderbilt University, Nashville, Tennessee, United States
Show AbstractClusters of EuS nanocrystals formed through the thermal assembly of small EuS nanocrystal monomers by varying the annealing temperature. At a low temperature, oleate ligands stabilized on the surface of the EuS nanocrystals, giving rise to their low solubility in oleylamine while facilitating monomer–monomer oriented attachment into short-chain structures. At a higher temperature, the oleate ligands thermally detached from the surface and were replaced by oleylamine. This reaction mechanism was a multilevel oriented attachment, based on calculations of the nanocrystal growth kinetics, whose evolution gave rise to the formation of EuS nanorods. The kinetics of the oriented-attachment nanorod growth is mainly controlled by van der Walls and Coulombic interactions between EuS nanoparticle monomers and the growing EuS nanorods. EuS nanoparticles were assembled into thin films through a facile electrophoretic deposition technique. Parameters associated with the films, such as thickness, surface roughness and porosity, were achieved by varying the deposition time, electrolyte, voltage and other deposition factors. By changing these parameters, the properties of the films were adjusted, such the optical and magnetic properties, etc.
9:00 PM - D9.23
Obtaining and Characterization of the Alumina-Zirconia Nanocomposites.
Eliria Pallone 1 , Kátia Silva 2 , Roberto Tomasi 3 , Vania Hernandes 4 , Cecilia Zavaglia 2
1 Ciências Básicas, Universidade de São Paulo, Pirassununga, São Paulo, Brazil, 2 Engenharia Mecanica, UNICAMP, Campinas, São Paulo, Brazil, 3 Engenharia de Materiais, UFSCar, São Carlos, São Paulo, Brazil, 4 , IPEN, São Paulo, São Paulo, Brazil
Show AbstractIn the last decades the search for materials with high hardness, good chemical stability, low density and good strength to high temperatures have driven the advances in studies of the special ceramic materials. One possibility to improve the properties these materials may be the use of the nanometric inclusions in the alumina matrix. Studies have shown that these nanocomposites have higher values strength and toughness compared with alumina. In the later 1980s, demonstrations of the expectations from the proposed approach were reported showing significant improvements in properties of ceramic matrix composites with the use of small amounts of nanometric inclusions of SiC. Additional studies have reported similar results with inclusions of SiC, TiC, NbC, and ZrO2 in alumina. In addition to providing evidence for property improvements, these studies have also attempted to provide an understanding of the strengthening mechanisms, although many observations and their interpretation remain a subject of some controversy. Nonetheless, there is convincing evidence of significant improvements in the properties of single-phase alumina ceramics, particularly with regards to hardness, wear resistance, strength and toughness. The objective of this work was to obtain and characterize nanocomposites of alumina ceramic matrix with nanometric zirconia inclusions, varying the amount of the 0, 5, 10, 15 and 30 vol% of zirconia inclusions in the alumina matrix, aimed improvements in the mechanical properties and in the wear of this material. For this, the nanometric zirconia inclusions were added in the alumina matrix in the different proportions, using mixture suspensions. After drying the powder and conformation, the specimens were sintered without pressure, using different temperatures. The nanocomposites obtained was characterized based on apparent density, microstructure, using a scanning electron microscopy, microhardness, diametral compression and toughness. The results of the microstructural analysis showed that the mixture suspension was efficient for a good dispersion of the zirconia inclusions in alumina matrix, showing that this is a simple process, economical and easy to perform. Also, it was observed the inhibition of grain growth of the alumina matrix with the increase of nanometric zirconia inclusions.The microhardness values remained constant for all compositions, but there was a slight increase in the values of the toughness and diametrical compression with the increased of the addition of nanometric zirconia inclusions. The general analysis of the results showed that the nanocomposite containing 15 vol% of nanometric zirconia inclusions presented the best results of the strength when compared with other compositions.
9:00 PM - D9.24
Hermetically Coated Nanosilver: No Ag+ Ion Leaching.
Georgios Sotiriou 1 , Samulel Gass 1 , Sotiris Pratsinis 1
1 Particle Technology Laboratory, ETH Zurich, Zurich Switzerland
Show AbstractNanosilver is prominent in several nanotechnology products. Here, nanosilver particles supported on nanostructured silica are made by flame synthesis [1] and in situ coated with a nanothin silica layer [2]. The morphology of the as prepared particles is investigated by X-ray diffraction, N2 adsorption and electron microscopy analysis. The Ag+ ion release when these composite nanoparticles are dispersed in water was investigated with an ion selective electrode. The nanosilver size could be precisely controlled by the process parameters, while the inert silica layer on the Ag+ ion release could successfully minimize it [3]. References[1] Sotiriou, G. A. & Pratsinis, S. E. Antibacterial activity of nanosilver ions and particles. Environ. Sci. Technol. 44, 5649-5654 (2010).[2] Sotiriou, G. A., Sannomiya, T., Teleki, A., Krumeich, F., Vörös, J. & Pratsinis, S. E. Non-toxic dry-coated nanosilver for plasmonic biosensors. Adv. Funct. Mater. 20, 4250-4257 (2010).[3] Sotiriou, G. A., Hirt, A. M., Lozach, P. Y., Teleki, A., Krumeich, F. & Pratsinis, S. E. Hybrid, silica-coated, Janus-like plasmonic-magnetic nanoparticles. Chem. Mater. 23, 1985-1992 (2011).
9:00 PM - D9.25
Effect of Particle Size on the Coercivity of Nd-Fe-B and Sm-Co Nanoparticles Prepared by Surfactant-Assisted Ball Milling.
Nilay Gunduz-Akdogan 1 , Wanfeng Li 1 , Dimitris Niarchos 2 , George Hadjipanayis 1
1 Physics and Astronomy, University of Delaware, Newark, Delaware, United States, 2 Institute of Materials Science, N.C.S.R. Demokritos, Athens Greece
Show AbstractAnisotropic Nd2Fe14B and SmCo5 nanoparticles have been produced by surfactant-assisted high-energy ball milling (HEBM) of nanocrystalline precursor alloys. A two-stage HEBM was performed to obtain the nanoparticles; first the coarse powders were made nanocrystalline by milling, and then were subjected to surfactant-assisted milling for 6 hr. Nanoparticles with different shape (irregular, square and spherical shapes) and size have been obtained by varying the time of the first stage milling. For a surfactant-free wet milling of 0.5 to 4 hr, anisotropic Nd2Fe14B and SmCo5 nanoparticles have been found with a size from 25 to 2.8 nm. The nanoparticles had coercivity values of 9 kOe for the 15 nm Nd2Fe14B and 15 kOe for the 25 nm SmCo5 at 50 K. The room temperature coercivities were lower with the values of 2.5 and 5 kOe, respectively. In the Nd2Fe14B nanoparticles, the spin reorientation was observed but at a lower temperature (117 K) than in bulk. The successful fabrication of Nd2Fe14B and SmCo5 anisotropic nanoparticles provides hope for the development of nanocomposite permanent magnets with enhanced energy products. Work supported by NSF DMR-1005871 and a Marie Curie Fellowship.Keywords: Nanoparticles, Ball milling, Coercivity, Surfactant.Corresponding author: Nilay G. Akdogan, University of Delaware, 217 Sharp Lab, Newark, DE 19716, U.S.A., Fax: 1-302-831-1637, Phone: 1-302-831-3515, E-mail:
[email protected].
9:00 PM - D9.26
Separation of Organic Chemicals and Heavy Metal from Water Using Novel Graphene Oxide-SiO2 and Graphene-SiO2 Nanocomposite Material.
Tanvir Alam 2 , Manoj Ram 1 , Farah Alvi 3 , Ajit Mujumdar 2 , Ashok Kumar 1 2
2 Department of Mechanical Engineering, University of South Florida, Tampa, Florida, United States, 1 Nanotechnology Research and Education Center, University of South Florida, Tampa, Florida, United States, 3 Deaprtment of Electrical Engineering, University of South Florida, Tampa, Florida, United States
Show AbstractGraphene exhibits unusual and intriguing physical, chemical and mechanical properties, and recently, has been used in molecular electronics, supercapacitors, sensors, biosensors, transparent conductors and photovoltaic cells. The graphene fabricated on silicon dioxide substrate shows interesting electronics properties by figuring out the local atomic configuration as well as identifying the binding sites of graphene with SiO2. Recently, we have synthesized and extensively characterized graphene (G) –silicon oxide (SiO2) and graphene oxide (GO) – SiO2 nanocomposites by varying graphene or graphene oxide with SiO2 precursor. We have observed highly conducting G- SiO2 and used them in battery application. This research is concerned with the separation of chemicals from G- SiO2 and GO- SiO2 nanomaterials. The organic chemicals (dichlorobenzene, acetic acid, xylene etc.) and heavy metallic ions of zinc, copper, lead and arsenic were separated at different concentrations using G-SiO2 and GO-SiO2 nanocomposite materials. Initially, 1 gram of synthesized G-SiO2 as well as GO-SiO2 nanocomposites was treated with 10 mM ZnCl2 solution separately in several beakers. The ZnCl2 (having whitish color) solution became transparent in one to two hrs by treating with G-SiO2 nanoparticles. The G-SiO2 absorbed and subsequently, decreases the concentration of concentration of ZnCl2. The water treated at different times was measured using gas Chromatograph –Mass spectrometer (GC-MS) and differential pulse voltammetry techniques. Later PbNO3, CuCl2, xylene chemicals were separated in similar fashion and water was measured using GC-MS technique. The heavy metal and organic chemical observed G- SiO2 and GO-SiO2 nanomaterials were dried, and characterized using Scanning Electron Microscopy (SEM), Raman spectroscopy, FTIR spectroscopy, X-ray-diffraction, electrochemical, and electrical measurement techniques. The recovery of G-SiO2 and GO-SiO2 nanoparticles were also made possible by treating the acid and basic media. Interestingly, the G-SiO2 nanocomposite containing equal ratio of SiO2 to graphene shows the better chemical separation properties than other observed composition. Our results indicate that the graphene–dioxide based nanocomposite could be future filter materials for drinking water.
9:00 PM - D9.27
Harnessing Molecule-Solid Duality for Control of Size, Shape and Alloying of Bimetallic Nanoparticles and Catalysts.
Jun Yin 1 , Lefu Yang 1 , Oana Malis 2 , Chuan-Jian Zhong 1
1 Department of Chemistry, State University of New York at Binghamton, Binghamton, New York, United States, 2 Physics, Purdue University, West Lafayette, Indiana, United States
Show AbstractMetal nanoclusters or nanoparticles exhibit molecule–solid duality in terms of molecule-like reactivity and nanoscale melting behavior. A key challenge if the ability to control both the molecular and nanoscale processes in terms of size, shape, and structures. This presentation describes the exploration of this novel concept as a new strategy to engineer size, shape, structure of different alloy nanoparticles for use in nanoengineering alloy catalysts for a variety of chemical reactions. One example involves structural evolution of binary copper and gold nanoclusters/nanoparticles towards alloy nanocubes. As revealed by different structural characterizations, especially the in–situ real time synchrotron x-ray diffraction characterization, the structural evolution of this binary nanoclusters/nanoparticles at or near the nanoscale melting temperatures leads to the preferred alloy nanocubes over their unary counterparts. The catalytic activities of the alloy catalysts for gas-phase CO oxidation and fuel cell reactions have been examined. Implications of the results to the design of advanced nanomaterials for green energy catalysis will also be discussed.
9:00 PM - D9.28
Colloidal Synthesis and Thermoelectric Properties of Cu2CdSnSe4 Nanocrystals.
Maria Ibanez 1 , Doris Cadavid 2 , Jordi Arbiol 3 , Juan Ramon Morante 1 2 , Andreu Cabot 1 2
1 Electronics department, University of Barcelona, Barcelona Spain, 2 Advanced materials for energy, Catalonia Energy Research Institute , Barcelona Spain, 3 , Institut de Ciencia de Materials de Barcelona, Bellaterra Spain
Show AbstractThermoelectrics has long been considered a very attractive technology for cooling and waste heat recovery. A promising strategy to improve the efficiency is the use of complex crystal structures allowing large electrical conductivities in thermally isolating materials. On the other hand, the reduction of the crystal domains to the nanoscale allows increasing the material’s thermoelectric figure of merit, mainly by further reducing its thermal conductivity. Moreover, the narrow electron energy bands of quantum confined structures usually have associated high effective masses and therefore large Seebeck coefficients. We present here a novel colloidal synthetic route to prepare quaternary adamantine nanocrystals with controlled size, shape and composition. We put special effort in designing a cost-effective and scalable process susceptible of being implemented in real applications. The synthetic route presented here is applied to the preparation of grams of the quaternary chalcogenide Cu2+xCd1-xSnSe4 (0 ≤ x ≤ 0.5) with accurately controlled composition and narrow size distributions. The electrical and thermoelectric properties of these materials were characterized over a wide temperature range. We will show how these materials have high Seebeck coefficients (150-300 uV/K), electrical conductivities up to 14000 S/m, and thermal conductivities down to 0.3 W/mK, leading to ZT values up to 0.4 at 700 K.
9:00 PM - D9.29
Graded Porous Silicon Carbide for High Temperature Membrane Applications.
Jyothi Suri 1 , Leon Shaw 1
1 Chemical Materials Bio-molecular Engineering, University of Connecticut, Storrs, Connecticut, United States
Show AbstractDue to its excellent thermal shock resistance, mechanical and chemical stability at both room and elevated temperatures, Silicon carbide (SiC) is an attractive material for environmental protection and energy production applications such as catalyst supports, molten metal filters and gas separation membranes. Precise pore size control and high porosity are the key deciding factors for such applications. The current study deals with the fabrication of SiC membranes with graded porous structures. The graded porous structure is achieved with layers of mesoporous nano-SiC and mesoporous amorphous Si-C-N thin film on the surface of a macroporous SiC support layer. Nano-SiC powders utilized for this study are synthesized using a novel process based on mechanical activation of silica fume and graphite mixtures, resulting in particle sizes as small as 30 nm. The effects of sintering temperature were investigated to control the pore size, pore volume fraction, surface characteristics, and gradient of the pore size.
9:00 PM - D9.3
Growth and Characterization of Aligned ZnO Nanorods and Nanoflowers Array and Their Application in Dye-Sensitized Solar Cell.
Saionara Costa 1 3 , Agnaldo Goncalves 2 , Talita Mazon 1 3 , Ana Flavia Nogueira 2 , Jorge Tomioka 3
1 DME, CTI, Campinas Brazil, 3 , UFABC, Santo André, SP, Brazil, 2 , Chemistry Institute - UNICAMP, Campinas, SP, Brazil
Show AbstractSuitable morphology for fast electron transportation is a crucial requirement for dye sensitized solar cells. In this work, highly vertically aligned zinc oxide (ZnO) nanorods and like-flowers 3D microstructures were grown on the FTO coated glass substrates using hydrothermal synthesis and a nucleation layer of ZnO. The nucleation layer it was obtained by using cheaper technology, such as the polymeric precursor method. The parameters for obtaining of the nucleation layer were adjusted according to previous results in order to optimize the morphology, thickness and uniformity of the films. During the hydrothermal synthesis, it was used different precursors: zinc nitrate, zinc acetate, potassium hydroxide or hexamethyldiamine. The parameters time, temperature, pH of the reaction was controlled aiming to obtain different morphologies. The final products were characterized by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FEG-SEM). The FE-SEM analyses were performed in the LME-LNLS. Different ZnO nanostructures were obtained, such as vertically aligned nanorods, like-flowers 3D, microrods, and so on. The DSSC solar cell configuration from the different ZnO nanostructures obtained has been used to record the current-voltage (I-V) and capacitance voltage (C-V) characteristics, fill factor (FF) and efficiency of the cells. The efficiency and Jsc of ZnO like-nanoflowers DSSCs were almost 4 times higher than efficiency and Jsc of DSSCs construed by vertically aligned ZnO nanorods. The efficiency increase is due to greatly enhanced surface area for higher dye loading and light harvesting.
9:00 PM - D9.30
Architectural and Compositional Control of Nanoparticles Composed of Bi, Sb, and Te by a Modified Polyol Synthetic Technique.
Kumar Prabhat 1 , T. Nguyen Mai 1 , Teruyoshi Sakata 1 , Sohel Shahiduzzaman 1 , Derrick Mott 1 , Shinya Maenosono 1
1 School of Material Science, Japan Advanced Institute of Science and Technology, Nomi City, Ishikawa prefecture, Japan
Show AbstractWith the advent of nanotechnology, the field of thermoelectric (TE) materials has been resuscitated with many recent advances towards high thermoelectric efficiency (dimensionless figure of merit, ZT). Since ZT=S2σT/κ, where S is the Seebeck coefficient, T is the absolute temperature, σ and κ the electrical and thermal conductivity, respectively, ZT can be increased either by reducing κ or by enhancing S2σ. κ can be significantly reduced through nanostructuring of the materials which increases phonon scattering, and considerable advances have been made along this direction using semiconductor nanostructures. On the other hand, S2σ, power factor, can be enhanced by tailoring the density of states (DOS) to approach the Fermi level, but this is challenging due to the need to preferentially control the electronic structure of the material. Researchers have made great strides in the ability to synthesize nanoparticles (NPs) composed of Bi, Sb, and Te with well-defined shapes or promising compositions. These NP based TE materials are highly interesting because the increased grain boundaries offer enhanced scattering of the heat carrying phonon. Despite the promise of NP based materials, few synthetic routes have shown flexibility in controlling both NP shape and composition, which is required to study the full range of properties. In our own research work, we have devised a synthetic technique towards NPs composed of Bi, Sb, and Te that is highly versatile in tuning both the composition and shape/structure of the resulting NPs. The ability to control these parameters is highly important as they dictate the resulting TE activity. In a modified polyol synthetic technique, it was found that a range of composition, shape, and structure combinations could be obtained for the NPs including Te/Bi2Te3 nanowires, Bi2Te3/Sb2Te3 nanorods, or BiSbTe3 platelets just to name a few. By further modifying the synthetic parameters such as temperature and reaction time, the particles characteristics could be additionally tailored, such as particle size. This is especially important because the NP size plays a key role in the suppression of κ and also plays a role in maintaining σ. This presentation focuses on our recent study of the synthesis of Bi, Sb, and Te composite NPs with unique shape/structure/composition and the implications to the design of highly efficient TE materials. The results are discussed using techniques such as HR-TEM, STEM-HAADF, EDS, XPS, and XRD, as well as others.
9:00 PM - D9.31
Direct Readout Solution Based SERS Detection of Thiram and Ferbam with Dogbone Shaped Gold Nanoparticles.
Benjamin Saute 1 , Radha Narayanan 1
1 Chemistry, University of Rhode Island, Kingston, Rhode Island, United States
Show AbstractThere is a need to detect many different environmental pollutants at trace levels (<1 ng/mL) for maintaining environmental safety standards set by the EPA. Thiram is a fungicide which is widely used in the field and in harvested crops. Surface enhanced Raman spectroscopy (SERS) is a phenomenon that results in greatly enhanced Raman signals when Raman scattering molecules are bound to metal substrates or to metal nanoparticles. Our method involves using dogbone shaped gold nanoparticles as SERS substrates and is a direct readout method for the quantitative detection of thiram and ferbam. The dogbone shaped gold nanoparticles are synthesized using the seed mediated growth method. The SERS intensity of the CN stretching mode is monitored as a function of different concentrations of thiram or ferbam bound to the gold nanoparticles. We have obtained dose-response plots and calculated the limits of detection (LODs) for our novel SERS based colloidal direct readout method. We will also present preliminary studies on the SERS detection of thiram and ferbam in real environmental media.
9:00 PM - D9.4
Synthesis of Ellipsoidal Silica Nanostructures.
Henan Zhang 1 , Daniel Akins 1
1 Department of Chemistry, The City College of The City University of New York, New York, New York, United States
Show AbstractWe have created ellipsoidal or spherical morphologies of silica particles in a template-free scheme that involves controlling surface tensions through selected volume ratios of a water/oil micellar system. And, a wet-chemical etching approach has been applied on ellipsoidal silica nanoparticles to form ellipsoidal silica nanoshells. The morphologies and structures of the nanoshells have been controlled by varying synthesis conditions. Furthermore, silica ellipsoidal nanoshells-Au nanocomposite catalysts have been prepared by functionalizing silica surface.
9:00 PM - D9.5
Synthesis and Characterization of Ag Nanoparticles Using PVP and PEG Blend.
Tilak Dahal 1 , Sanjay Mishra 1 , Zachery Glenn 1
1 Department of Physics, Univ Memphis, Memphis, Tennessee, United States
Show AbstractAg nanoparticles find wide applications from electrical to biomedical applications. Most of the techniques to synthesis Ag NPs produce wide dispersibility and agglomeration of nanoparticles. The problem of disperisibility is partially overcome by using stabilizing agents such as PVP, PEG, PVA, ethylene glycol. In general majority of Ag NPs synthesis strategies revolve around tuning the shape and size of nanoparticles for applications such as localized surface plasmon resonance in the presence of visible light. The efforts in changing shape and size largely depend on using suitable polymeric stabilizing, reducing agent, and temperature. Overall mol. wt. of polymers have been found effective in altering the structural properties of Ag NPs by offering space available for encapsulating the reduced Ag ions and thus bringing in a change in the size and shape of Ag NPs. Here in a novel approach is presented to change shape and size of Ag NPs by changing free space of PVP. This engineering is achieved by systematically adding a plasticizer PEG into the PVP. It has been reported earlier that PEG when added to PVP in a small concentration act as a plasticizer bonding to PVP chains. Thus, the available space for the growth of Ag NPs between PVP molecules can be modified by the addition of PEG. Ag NPs were prepared using nitrate salt of Ag, glucose, and PVP (MW=40 k) and PEG (10 k). Samples with varying PVP/PEG weight ratios, x, were prepared in (1-x) PVP-(x) PEG formulation. The XRD patterns of as prepared Ag NPs show asymmetric peak intensity at 2Θ=38.36 and 44.55o. The observed asymmetry in the peak intensity arises from the preferred orientation of NPs and hence indicates degree of asphericity in 0.3〈x〈0.8 Ag NPs as compared to x = 0 and 1 samples. TEM analysis shows that in the presence of pure PVP (x=0) and PEG (x=1), Ag NPs favored sphere-like shape with an average diameter of 55 nm and 49 nm, respectively. The presence of asymmetric Ag NPs (~35 nm) was observed for all other concentration of PEG. The presence of asymmetrical Ag NPs in PVP-PEG-Ag nanocomposite is further confirmed via red shifts in Uv-vis spectroscopy. The high SERS signals of benzoic acid in the Ag NPs in the range 0.3〈x〈0.8 also confirms the presence of asymmetric Ag NPs. The growth of Ag NPs in the presence of PVP/PEG is attributed to the free space available to the Ag ion growth. At PEG concentration (x〈0.3), PEG attaches to PVP but at higher PEG concentration (0.3〈x〈0.8), PEG cross-links PVP strands and reduces the available free space for the growth of Ag NPs. Due to cross-linking, the PVP/PEG blend behaves as completely different kind of polymer with lower melting point from their pristine counterparts. Thus, here in we present a novel approach for the synthesis of nanostructured material by controlling the free volume space between the polymer chains. Our approach can be extended to the synthesis of other metal NPs.
9:00 PM - D9.6
Efficient Noble Metal Catalysts for Different Organic Reactions.
Mallampati Ramakrishna 2 , Valiyaveettil Suresh 2
2 Chemistry, National University of Singapore, Singapore Singapore
Show AbstractHeterogeneous catalysts are important in many industrial processes. Here we report a template assisted synthesis of heterogeneous nanoparticle catalysts and their catalytic efficiency towards different organic reactions. Natural membranes are used as a templates, which not only acts as supporting material but also showed interesting reducing and stabilizing properties. The metallic nanoparticle catalysts were characterized using UV-Vis spectroscopy, FESEM, and XPS studies. As a proof of concept, the resultant membrane supported nanoparticles were used as heterogeneous catalyst for the reduction of 4-nitrophenol and synthesis of propargylamine. Both catalytic activity and recyclability make these catalysts interesting candidate for further studies.
9:00 PM - D9.8
Catalytic and Biomedical Application Potential of Ferritin-Encapsulated Metal Nanoparticles.
Mato Knez 1 , Lianbing Zhang 1
1 , Max-Planck-Institute MSP, Halle Germany
Show AbstractSome inorganic nanoparticles resemble certain catalytic properties of natural biological enzymes. In principle, this could enable a substitution of enzymes with corresponding nanoparticles for cellular or biomedical applications. However, surface modifications to the nanoparticles are in most cases necessary to enhance the biocompatibility. The protein cage of ferritin, a major cellular iron storage protein, serves not only as reusable template for the size-constrained synthesis of nanoparticles but also as vehicle for a cellular delivery. Once encapsulated in ferritin, a cellular incorporation of nanoparticles is proceeding via ferritin-receptor mediated endocytosis.As an example, platinum, gold, or metal alloy nanoparticles were prepared in the cavity of hollow protein nanospheres of ferritin (apoferritin). The use of such bioinorganic nanocomposites has several advantages, among them the cheap and straight-forward synthesis and the reusability of the particles. Applications range from catalytic seeds for nanowire growth to biomedical applications. As an example, Pt-apoferritin (Pt-apo) nanocomposites showed excellent H2O2 and superoxide scavenging activity and their efficiency could be tuned by adjusting various experimental parameters. The catalytic activities of the Pt-apo composites resemble two cellular enzymes - catalase and superoxide dismutase, which are responsible for the cellular antioxidative defense. Ferritin templates were beneficial for potential anti-stress applications of such nanocomposites in life science. Tests on human intestinal Caco-2 cells proved the receptor-mediated cellular incorporation of Pt-apo. Under externally induced stress with, for example, hydrogen peroxide, the reactive oxygen species in Pt-apo treated cells decreased, resulting in an increased viability of the cells. The possibility to switch on and off the endocytosis, the natural cellular uptake pathway of ferritin, and the revealing biological functions of the protein may bring about new perspectives for biomedical applications of nanomaterials.
9:00 PM - D9.9
A Continuous Mass Fabrication Process for SiNWs with Prescribed Lengths.
Jungkil Kim 1 2 , Hyun Rhu 1 , Woo Lee 1 2
1 , Korea Research Institute of Standards and Science (KRISS), Daejeon Korea (the Republic of), 2 Department of Nano Science, University of Science and Technology (UST), Daejeon Korea (the Republic of)
Show AbstractThe synthesis of structurally well-defined one-dimensional nanostructures of silicon has attracted considerable efforts due to the potential use of the structures in both mesoscopic research and the future development of nanodevices. We report a simple top-down approach for the continuous mass preparation of single crystalline SiNWs with controlled lengths and axial crystal orientations. Our approach is based on periodic pulsing of anodic bias during metal-assisted chemical etching of a silicon substrate using a gold mesh with ordered arrays of nanoholes and subsequent ultrasonic treatment of the resulting porosity-patterned SiNWs for selective breakage of nanowires at the porous segments. In our process, the pulse interval defines the length of nanowires, while the size of nanoholes in gold mesh determines the diameter of SiNWs. Moreover, after nanowire separation by ultrasonic treatment, the remaining metal mesh-loaded silicon substrate can be reused for additional preparation of SiNWs with desired lengths. In this presentation, the advantages of the present nanofabrication process over the conventional bottom-up growths of SiNWs will be discussed in detail.Authors:Presenting author: Jungkil Kim, E-mail:
[email protected] author: Woo Lee, E-mail:
[email protected], Tel: +82-42-868-5397
Symposium Organizers
" " " Brookhaven National Laboratory
Mato Knez Max Planck Institute of Microstructure Physics
Stanislaus S. Wong State University of New York at Stony Brook
Hongjin Fan Nanyang Technological University
Woo Lee Korea Research Institute of Standards and Science (KRISS)
D10: Sensing and Materials for Sensing
Session Chairs
Thursday AM, December 01, 2011
Back Bay B (Sheraton)
9:30 AM - **D10.1
Controlling the Sensitivity, Specificity, and Time Signature of Sensors through Architectural Design on the Nanoscale.
Debra Rolison 1
1 Surface Chemistry, U.S. Naval Research Laboratory, Washington, District of Columbia, United States
Show AbstractArchitectural nanoscience, i.e., the design and fabrication of three-dimensional multifunctional architectures from the appropriate nanoscale building blocks, presents a new tactic to optimize catalytic chemistries, energy storage and conversion, biomolecular composites, porous magnets, and sensors [1,2]. Advanced architectures can now be created in which the pore and solid structural components are controlled on the nanoscale by the use of sol-gel syntheses, including the use of metal oxide sols to nanoglue appropriate guests into the solid network. By removing the pore fluid of a wet gel under conditions of minimal-to-no surface tension to yield either ambigels or aerogels, respectively, ultraporous nanoarchitectures are created that intimately blend being (a nanoscale solid network) and nothingness (a continuous, pore network).The architectural nature of such structures makes them especially well suited to sensors, reactors, and tailored platforms, in which rapid transport of detectable, reactive, or modifying species and readily accessible surface areas are critical to performance. The response time of aerogel-based sensors to gas-phase analytes, whether using luminescent, colorimetric, biomolecular, or electrochemically responsive moieties, occurs at rates commensurate with open-medium diffusion of the analyte. The same chemistries expressed in standard sol-gel-derived materials such as xerogels (which are dried from polar media and experience pore collapse) are at least 100 times slower. Without fully open plumbing, one truly wastes time.[1] J.W. Long and D.R. Rolison, Acc. Chem. Res. 2007, 40, 854–862.[2] D.R. Rolison, J.J. Pietron, and J.W. Long, ECS Trans. 2009, 19(6), 171–179.
10:15 AM - D10.3
A Facile Synthesis of Ag@AgCl and AgCl Nanostructures: Their Optical and SERS Properties along with Their Decompostion to Form Highly Textured Silver Nanomaterials.
Eric Formo 1 , Sheng Dai 1
1 CNMS, ORNL, Oak Ridge, Tennessee, United States
Show AbstractRecently new applications for materials composed of Ag@AgCl and AgCl have led to novel developments in synthetic techniques to produce such materials. Herein we report on the facile synthesis of Ag@AgCl cube-like nanostructures by the addition of Rhodamine 6G into a polyol reduction reaction. Subsequently, it was found that the addition of high concentrations of HCl resulted in the formation of AgCl cube-like nanostructures. Moreover, by removing PVP from the reaction mixture Ag@AgCl coral like structures could also be produced. Interestingly, when these materials are placed under an electron beam localized heating will cause the decomposition of the AgCl components thereby prompting the formation of cubic-like highly roughened silver nanomaterials. Further, we will also discuss new applications for Ag@AgCl cubes in which the silver regions on the surface of these nanostructures have excellent plasmonic properties, causing these materials to be useful in surface enhance Raman spectroscopy (SERS) applications.
10:30 AM - D10.4
Room Temperature Stabilization of Citrate Capped Ag Nanoparticles in Mesoporous ZrO2 Thin Films.
Manish Kumar 2 1
2 , Indian Institute of Technology Delhi, New Delhi India, 1 , Inter University Accelerator Centre, New Delhi India
Show AbstractAg:ZrO2 nanocomposite thin films have been synthesized at room temperature by soaking sol-gel derived mesoporous zirconia thin films into a solution containing citrate capped Ag nanoparticles. The growth mechanism of Ag nanoparticles in the case of either embedding in mesoporous zirconia or dispersing on glass substrate thin film has been investigated in view of stability of optical properties. The fine structure of the plasmon resonance absorbance peak was found in the films. Optical studies show a surface plasmon resonance induced absorption centered on 440 nm. TEM study reveals the formation of spherical shaped Ag nanoparticles embedded in ZrO2 matrix. The average size of uniformly distributed Ag nanoparticles is 12 nm. Increase in percolation duration leads to increase the density of Ag nanoparticles. Chemical study reveals that Ag is in its elemental state and not chemically bonded with the matrix.
10:45 AM - D10.5
Fast Fabrication of Nano-Structured Filament by Electrochemical Migration (ECM) Method.
Min-Suk Jung 1 , Shin-Bok Lee 1 , Ho-Young Lee 1 , In-Suk Choi 2 , Young-Chang Joo 1
1 , seoul national university, Seoul Korea (the Republic of), 2 , Materials Science and Technology Division, Korea Institute of Science and Technology, Seoul Korea (the Republic of)
Show Abstract A new method to fabricate metal and metal oxide nanostructured metal filament by electrochemical migration (ECM) method is demonstrated in this study. ECM is the phenomenon of the formation of nano-sized conductive metal filaments. When DC bias is applied on adjacent metal electrodes under the liquid electrolyte, anode electrode becomes electrochemically unstable and responds to applied voltages by electrochemical ionization of metal. These dissolved cations move from anode to cathode through the electrolyte by electric field and are reduced at cathode and grow forward to anode in the form of tree-like dendritic metal filament, of which the diameter is normally in the range of tens or hundreds of nano-meters. Stated simply, ECM consists of the following 3 steps: metal dissolution, migration of metal ions and conducting filament formation and growth. It is reported that this ECM phenomenon is taken place on various metal such as Ag, Sn, Cu, Au, Pb, Pd, Pt, and Bi. Therefore, various nano-sized metal filaments from these metals can be easily obtained and even grow just in minutes during this electrochemical migration method. We demonstrate the possible application of silver nanowire, produced by ECM method, into manufacturing the hydrogen sensing device. Pd for the active sensing material has unique property of interaction with hydrogen gas. However, pure Pd has some limitations of ‘peeling-off’phenomenon. This limits the durability of sensor and it causes a slow response at low partial pressure. As pure Pd is noble metal, its resistance of the dissolution is high, resulting in not allowing the ECM process. Instead, Pd-Ag nanowire system was applied to hydrogen sensor. Dendritic Ag nanowire is fabricated prior to the Pd thin film deposition. Electrode of Ag was fabricated on the oxidized wafer by thermal evaporator with a patterned screen mask. Electrolyte, distilled water, was dropped between anode and cathode and DC bias of 0.5~3.0 V is applied between Ag electrode for 2~3 minutes. The diameter of this nanowire is 50-200 nm thickness. After that, as Ag nanowire, with 20-500 nm thickness, is covered with Pd thin film, the newly produced sensors have high surface-to-volume ration and prevent the ‘peeling off’ phenomenon. As a result, they have a good magnitude of response, fast response time, high durability. Pd-coated Ag dendrites showed shorter response times (315.7 s) and somewhat higher magnitudes of response (5.34 %) than those of metal Pd thin films (response time: 572.1 s, magnitude of response: 5.09 %). We suggest that this low-cost and easy fabrication ECM method can be also applied to various metal and metal oxide nanowire followed by oxidation process by annealing treatment after producing metal nanowire for potential applications such as gas sensors, catalyst support, transparent conducting electrodes and lithium ion battery anode materials.
11:00 AM - D10:: Sens
BREAK
D11: Bio-Degradation and Bio-Assisted Synthesis
Session Chairs
Thursday PM, December 01, 2011
Back Bay B (Sheraton)
11:30 AM - **D11.1
Coating Anti Bacterial, Anti Viral, Antibiofilm and Antifungi Nanoparticles on Various Substrates Employing the Sonochemical Method.
Aharon Gedanken 1
1 , Bar-Ilan University, Ramat-Gan Israel
Show AbstractThe coating of textiles were probed on polyester, cotton, nylon , and nonwoven. In all cases a homogeneous coating of NPs was achieved. Silver is known for generations as antibacterial, and indeed the Ag NPs have killed the gram-negative E. Coli (strain 1313) as well as the gram-positive Staphylococus aureus (strain 195) bacteria very efficiently1. Lately, since the FDA shows less enthusiasm towards Ag we have moved to NPs of ZnO, CuO and MgO as antibacterial agents. They were coated on the above-mentioned fabrics and showed excellent antibacterial properties2. The coated textiles were examined for the changes in the mechanical strength of the fabric. A special attention was dedicated to the question whether the NPs are leaching off the fabric when washed repeatedly. Lately the coated ZnO NPs on cotton underwent 65 washing cycles at 92 0C in water in a Hospital washing machine, no NPs were found in the washing solution and an the antibacterial behavior was maintained. Our vision is that all the textiles in the Hospitals of the future will coated by antibacterial NPs.MgF2 NPs coated on glass have demonstrated Antobiofilm Acitivity. The ability of bacteria to colonize abiotic surfaces and develop biofilms is a major cause of medical implant-associated infections and results in prolonged hospitalization periods and patient mortality. Here, we report on the synthesis of nanosized fluorides materials (MgF2 Nps) and we prove the affecting interactions with bacterial cells by mechanical, potential damages to the membrane and the possibility to interact with nucleic acids. We have extended these first attempts and coated Latex catheters by these MgF2 NPs. The coated catheters showed resistance to the development of biofilms on their surface. The antiviral activity of Ag- or Au-MES (mercaptoethanesulfonate) against HSV-1 and 5 different influenza viruses will demonstrated. References1)Perelshtein, I. , Applerot, G. , Perkas, N. , Guibert, G. , Mikhailov, S. , Gedanken, A. NANOTECHNOLOGY, 19, Article Number: 245705 (2008). 2)Perelshtein, I. , Applerot, G. , Perkas, N. , Wehrschetz-Sigl, E. , Hasmann, A. , Guebitz, G. M. , Gedanken, A. ACS APPLIED MATERIALS & INTERFACES, 1, 363-366 (2009).
12:00 PM - D11.2
Microbial Reduction of Graphene Oxide by Shewanella under Ambient Conditions.
Fang Qian 1 2 , Gongming Wang 2 , Chad Saltikov 3 , Jeffrey Gralnick 4 , Yongqin Jiao 1 , Yat Li 2
1 Physical and Life Sciences Directorate, Lawrence Livermore National Lab, Livermore, California, United States, 2 Department of Chemistry and Biochemistry, University of California, Santa Cruz, California, United States, 3 Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, United States, 4 BioTechnology Institute and Department of Microbiology, of Minnesota-Twin Cities, St. Paul, Minnesota, United States
Show AbstractWe report reduction of graphene oxide to graphene under ambient conditions as mediated by microbial respiration of Shewanella oneidensis MR-1 cells. The microbially-reduced graphene exhibits excellent structural, electrical and electrochemical properties. The extracellular electron transfer pathway(s) at the cell/graphene oxide interface were investigated systematically, by analyzing a range of mutants lacking these proteins and/or adding electron-shuttling compounds. We determined that graphene oxide reduction by MR-1 requires the Mtr respiratory pathway. These results may help facilitate the use of non-pathogenic bacteria for large-scale green synthesis of graphene. This work was performed under the auspices of the U.S. Department of Energy Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
12:15 PM - D11.3
A Simple and Green Method for Synthesis of Ag and Au Nanoparticles Using Biopolymers and Sugars as Reducing Agent.
German Ayala 1 , Luci Cristina Vercik 1 , Leticcia Ferreira 1 , Andres Vercik 1 , Thiago Antonio Villa Menezes 1
1 Basic Sciences Department - FZEA, Universidade de Sao Paulo, Pirassununga - SP Brazil
Show AbstractGold and silver nanoparticles have been studied over time because their electrical, chemical, magnetic, optical, electronic and thermal properties that presents applications in several areas of nanoscience and technology. The properties of nanoparticles are based on the size, shape and surface morphology. Conventional methods for producing nanoparticles involve the use of organic solvents and toxic reducing agents that generate environmental risk. The partial or total elimination of waste along with sustainable processes is known as green chemistry, which employs nontoxic chemical and renewable materials. The synthesis of nanoparticles using sugar as reducing agent usually requires long times or high temperatures for processing, however sugars as starch are very cheap, bio-friendly and do not need the use of organic solvents. Traces of organic solvents in nanoparticles limit their applications in biological systems. Green synthesis can produced nontoxic nanoparticles that are stable under in vivo conditions for potential applications in nanomedicine and food industry.In this work, the synthesis of Ag and Au nanoparticles (AgNP and AuNP) was studied utilizing chitosan, starch, sucrose, lactose, maltose, glucose, galactose and fructose as reducing agent at different temperatures. The UV-Vis spectroscopy allows visualizing the formation of the AgNP in solution based on the 417-434nm surface plasmon band, this observation indicates the formation of Ag particles of nanometer-sized in the different solutions. All solutions with Ag nanoparticles showed a broad peak in the UV-Vis spectra, indicating the existence of Ag nanoparticles with different size, being stronger when sucrose has been used as reducing agent. We obtained a plasmon absorption peak at 419nm for the nanoparticle synthetized with chitosan, with increasing wavelength when starch and sugars were used, coming to be 434nm for nanoparticles synthetized with glucose. Increasing of plasmon absorption peaks is associated with increasing of sized in the nanoparticle. For higher bath temperatures, from 40°C to 90°C, sharper peaks were observed, probably due to increasing reaction rate for AgNP synthesis. AuNPs were synthetized with chitosan at different temperatures, however, usage of starch and sugars as reducing agent resulted in more critical dependence on reaction parameters such as pH. We observed a precipitate in the solutions using starch and sugars. Thus, although Au was reduced, unstable solution with AuNP where obtained. This and can be attributed to acid environment (pH∼4) where AuNPs do not generate insufficient repulsive force for colloid stability is generated and then the AuNPs coalesced.
12:30 PM - **D11.4
Remediation of Environmental Contaminants with Active Metal Particles in Liquid Membrane Systems.
Cherie Geiger 1 , Christian Clausen 1 , Jacqueline Quinn 2
1 Chemistry, University of Central Florida, Orlando, Florida, United States, 2 , NASA Kennedy Space Center, Kennedy Space Center, Florida, United States
Show AbstractMetal particles have been used for abiotic environmental remediation for the past fifteen years, mostly for reductive dehalogenation of chlorinated ethanes and ethenes, and sequestration of some dissolved toxic metals. Zero valent iron (nanoscale, microscale, and larger) has been the most common metal used for these purposes. However, other active metals have potential uses and have been field-tested successfully with contaminants that showed little or incomplete degradation with iron. For instance, polychlorinated biphenyls, polybrominated diphenylethers, chlorinated pesticides, and chlorinated dioxins can be effectively degraded with microscale magnesium or magnesium ball-milled with graphite. One of the challenges with remediation of organic compounds lies in the ability of the remediation agent to access the contaminant. Many of these compounds bind to the organic portion of the soil or sediment particles which inhibits the ability of a metal particle to efficiently interact with the contaminant. Liquid membrane systems can incorporate the use of emulsions, pastes, and foams and can sometimes be used as a tool for desorbing the contaminant organic materials from bound surfaces. They can also be formulated to sorb contaminants from materials other than soils and sediments such as paints, sealants, or concrete, thus allowing for reduction by the active metal within the liquid membrane system itself.This presentation will provide an overview of the University of Central Florida Environmental Chemistry Laboratory research and field-scale demonstrations of nanoscale and microscale iron or magnesium particle/liquid membrane systems for degradation of several different contaminants in a variety of matrices.
D12: Water Purification and Separation
Session Chairs
Thursday PM, December 01, 2011
Back Bay B (Sheraton)
2:30 PM - D12.1
Ultrafine α-Fe2O3 Nanoparticles Grown in Confinement of In Situ Self-formed ``Cage'' and Their Superior Arsenic Adsorption Performance for Water Purification.
Wenshu Tang 1 , Qi Li 1 , Caifu Li 1 , Shian Gao 1 , Jian Shang 1 2
1 Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, Liaoning Province, China, 2 Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
Show AbstractWithout the addition of surfactants or templates, ultrafine α-Fe2O3 nanoparticles were successfully synthesized by a solvent thermal process at low temperature. During the synthesis, in-situ self-formed "cage" of crystallized NaCl confined the growth of α-Fe2O3 nanoparticles in both the precipitation and solvent thermal processes, resulting in the creation of well crystallized α-Fe2O3 nanoparticles with an average particle size about 4 to 5 nm and a high specific surface area of ~ 162 m2/g. High resolution TEM investigations provided clear evidences of the in-situ self-formation of NaCl "cage" during the synthesis and its confinement effect on the growth of α-Fe2O3 nanoparticles. The arsenic adsorption experiment results demonstrate that they were effective, especially at low equilibrium arsenic concentrations, in removing both As(III) and As(V) from lab-prepared and natural water samples. Near the neutral pH, the adsorption capacities of the α-Fe2O3 nanoparticles on As(III) and As(V) from lab-prepared samples were found to be no less than 95 mg/g and 47 mg/g, respectively. In the presence of most competing ions, these α-Fe2O3 nanoparticles maintained their arsenic adsorption capacity even at very high competing anion concentrations. Without the pre-oxidation and/or the pH adjustment, these α-Fe2O3 nanoparticles effectively removed both As(III) and As(V) from a contaminated natural lake water sample to meet the USEPA drinking water standard for arsenic.
2:45 PM - **D12.2
Merging Self-Assembly with Atomic Layer Deposition to Mimic Biological Water Purification Membranes.
C. Jeffrey Brinker 1 , Ying-Bing Jiang 3 , Shaorong Yang 3 , David Rogers 2 , Kevin Leung 2 , Susan Rempe 2
1 , Sandia Natl Labs/UNM, Albuquerque, New Mexico, United States, 3 Univerity of NM Dept. of Earth and Planetary Sciences, Sandia National Laboratories, Albuquerque, New Mexico, United States, 2 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractNatural systems have evolved to solve complex engineering problems, like optimizing weight and stiffness, self-cleaning, adhesion, and water purification, using hierarchical structures composed of multiple, often disparate, materials arranged on differing prioritized length scales. Mimicking these proven materials designs in robust engineering materials with efficient processing strategies to achieve synergistic, optimized properties and combinations of properties is a current grand challenge. This talk highlights combining bottom-up evaporation-induced self-assembly with top-down atomic layer deposition as a nanofabrication strategy to enable efficient formation of hierarchical porous and composite structures with optimized property combinations. As a model system we consider natural water purification channels, aquaporins, whose asymmetric pore surface chemistry and channel dimensions evolved to maximize the combination of high water flux and ion rejection. Since ions and water molecules are similar in size, membrane pores cannot separate ions from water by size alone. Instead, the surface chemistry and architecture of each membrane pore must be delicately controlled to tune chemical interactions with water and ions that lead to efficient water purification and high water flux. Here using evaporation-induced self-assembly we create large scale silica membranes with 2.3-nm diameter pores. Further atomic-layer deposition of amides creates nanoporous polypeptide-like membranes with two key structural elements important to high water flux and ion rejection: multiple chemical functionality in asymmetric arrangements of hydrophilic amide and hydrophobic aromatic chemical groups and a narrow and thin pore architecture. At low pressures around 5.5 bar, the biomimetic membrane achieves an order-of-magnitude improvement in membrane permeability compared to commercial membranes and still maintains high salt rejection ratios. If the small-scale biomimetic membrane were embedded in a large-scale format, the improved performance would translate into a projected savings of 88% of the cost due to the membrane resistance to flow.
3:15 PM - **D12.3
Nanofiber Membrane for Producing Drinking Water and Energy from Wastewater Concurrently.
Darren Sun 1
1 School of Civil and Environmental Engineering, Nanyang Technological University, Singapore Singapore
Show AbstractEnergy and drinking water scarcity are some of today's most pressing challenges. Rapidly industrialization and expanding population, coupled with increasing environmental standards, are straining natural resources that are also afflicted with climate change. Cost effective water reclamation has become the most viable means of meeting demand in many places. Conventional pressure driven polymer based filtration membranes have been widely used for the production of drinking water with a small footprint size. However, huge amount of energy (electricity) is needed for the pressure driven polymer based membrane water production. In addition, these membranes have high fouling problems resulting in evener high energy consumption of drinking water production as another obstacle. In These obstacles paint the image of ‘energy intensive’ thus possess a major challenge with the need to curb greenhouse gases. Forward osmosis (FO) is a natural process which exhibits unparalleled advantages of no external energy input, nearly complete rejection of many contaminants and extremely low membrane fouling tendency. Hence it represents a tremendous and untapped opportunity with the potential to solve the global water crisis. The biggest challenges facing the FO application of associated with water reclamation technology are (1) the lack of an ideal draw solute, which can be separated from water with a more energy-efficient process for reuse; and (2) the lack of an appropriate FO membrane with high water flux for large water productionTremendous efforts have been put in this area by our research group. This presentation will discuss the application of nanofibers for the fabrication of a novel nanocomposite FO membrane with the perspective in the use of FO membrane together with anaerobic reactor for concurrent drinking water and bio-energy production from wastewater. Finally, areas needed for further researches to improve the nanotechnology will be discussed.
3:45 PM - D12.4
Water Transport in MFI Zeolite Pores.
Thomas Humplik 1 , Shalabh Maroo 1 , Tahar Laoui 2 , Evelyn Wang 1
1 Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran Saudi Arabia
Show AbstractWe investigated water transport in MFI zeolites with experiments and modeling for the development of high performance water desalination membranes. While state-of-the-art reverse-osmosis membranes are limited by diffusion, zeolite-based membranes promise faster water transport while maintaining high salt rejection. However, there is currently limited fundamental understanding as to how water molecules transport through subnanometer (3-8 Å) pores in zeolite crystals. In this work, we synthesized MFI zeolites using hydrothermal synthesis. We studied water transport by applying hydraulic pressure and measuring the change in system volume of the zeolites suspended in water. Water infiltration was observed at an applied pressure of approximately 60-80 MPa, which corresponds to a volume change of 0.08 cm3 per gram of zeolite. The results suggest that approximately 42% of the available pore volume is filled with water. We simultaneously modeled this infiltration behavior using molecular dynamics and determined the appropriate simulation parameters using the experiments to provide additional insight into the transport mechanisms. In addition, we quantified the amount of adsorbed water within these zeolite pores using thermogravimetric analysis. The results indicate that 9.05 ± 1.41 mg of water per gram of zeolite is already present in the pores under ambient conditions. Collectively, these studies offer a first step towards understanding and predicting transport behavior through zeolite-based membranes.
4:00 PM - D12: Water
BREAK
D13: Controlled Growth
Session Chairs
Thursday PM, December 01, 2011
Back Bay B (Sheraton)
4:30 PM - D13.1
Controlling and Preserving the Shape of Metallic Nanocrystals for Sustainable Applications.
Yujie Xiong 1 2
1 School of Chemistry and Materials Science, University of Science & Technology of China, Hefei Anhui China, 2 School of Engineering and Applied Science, Washington University in St. Louis, Saint Louis, Missouri, United States
Show AbstractMastery over the geometrical shape of a nanocrystal enables control of its properties and enhances its usefulness for a given application. A great deal of effort in the past decade has been directed toward controlling nanocrystal shape. Most recently, it has been discovered that the shape of a nanocrystal can undergo dynamic changes in response to variations in the surrounding environment, affecting the functionality of nanomaterials in turn. In this presentation, I will demonstrate new approaches to control and preserve the shape of nanocrystals from two different angles, using face-centered cubic (fcc) metals as a model system. Firstly, I will illustrate how to create the shape of a nanocrystal by manipulating parameters such as oxidative etching and capping agents. Secondly, I will elucidate some mechanisms involved in the morphological changes of nanocrystals in aging process, which can help us define rules for preserving the shape of nanocrystals in the future. Finally I will demonstrate some sustainable applications of nanocrystals benefited from the shape control. It is anticipated that this series of works will open a door to the synthesis of nanomaterials for preserving a green, sustainable environment.
4:45 PM - D13.2
Synthesis and Catalytic Property of NiPt Nanocubes Synthesized by Alcohol Reduction Method.
Jeyadevan Balachandran 1 , Jhon Cuya Huaman 1 , Hiroshi Miyamura 1 , Shunya Fukao 1 , Kozo Shinoda 2
1 Material Science, The University of Shiga Prefecture, Hikone Japan, 2 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai Japan
Show AbstractIntroductionNickel is considered for catalytic applications and considerable researches have been devoted to synthesize single nanometer sized particles; however, recent interest has been to synthesize nickel–platinum alloy catalyst as a replacement for platinum in fuel cell applications. Though nickel–platinum nanoparticles with various sizes and compositions were obtained by controlling the thermodynamics and kinetics of the reaction, less effort was made to control their morphology. In this paper, we report the synthesis of novel cubic shaped-standing Ni–Pt alloy nanoparticlesis with sizes ranging between 30 and 10 nm using alcohol reduction method. ExperimentalIn a typical procedure to synthesize Ni and Ni–Pt nanoparticles, 38 mM nickel salt was totally dissolved in 5 mL methanol using ultrasonication. The above solution was mixed with 100 mL 1-heptanol containing 0.42 M of oleylamine and a specific dihydrogen hexachloroplatinate concentration and, then, heated at 448Kfor 60 min. The particles were recovered by using a magnet, washed with a mixture of methanol and toluene in order to remove unreacted compounds and excess oleylamine. Finally, the particles are dispersed in toluene.ResultsThe experimental investigations have suggested that the presence of (i) specific concentration of Pt ions, (ii) chloride ions and (iii) oleyl amine concentration influences the shape and size of NiPt nanoparticles. The influence of chloride ions and oleylamine on the formation of various shapes has been already established by researchers working on the synthesis metal nanoparticles. However, the formation of cubic-shaped Ni-Pt alloy nanoparticles have been found to depend on the incorporation of a few percent of Pt atoms in the presence of chloride ions and oleylamine, which helps to control the growth and prevents agglomeration, facilitates the formation of highly monodispersed cubic shaped particles. The particle sizes could be varied between around 30 and 15 nm by controlling the reaction conditions. However, further reduction in size to around 10 nm was only possible by introducing 3-4 nm Pt particles as seeds. The catalytic activities of the particles have been evaluated by hydrogenation reaction of 1-Octene to Octane. The catalytic activity of 10 nm sized Ni90Pt10 particles were comparable to that of 3-4 nm diameter Pt particles when the difference in surface area is taken into account.
5:00 PM - D13.3
Growth of PtFe Nanostructures Observed by In Situ Liquid Cell Transmission Electron Microscopy.
Hong-Gang Liao 1 , Haimei Zheng 1
1 Materials Sciences Division, Lawrence Berkeley Natl Lab, Berkeley, California, United States
Show AbstractSynthesis of nanomaterials using colloidal solution processes has attracted great interest since it offers the massive scalability that is required for any global energy solution. Although significant advances have been made on the growth of nanocrystals, mechanisms of growth remain controversial. For example, different growth mechanisms have been proposed for the growth of one-dimensional or other complex nanostructures, i.e., oriented attachment, reversible micelle restricted growth, or surface facet controlled monomer attachment, etc. In this work, we study PtFe nanostructure growth in solution using in situ liquid environmental cell transmission electron microscopy (TEM). By controlling surfactant and composition of the growth solution, PtFe nanostructures with different shape and morphologies have been achieved. We have observed in real time that nanoparticles act as building blocks for the formation of complex nanostructures. The morphologies of the nanostructures are strongly dependent on the size of the nanoparticle components. The inter-nanoparticle interaction and surfactant effects will be discussed based on our observation. We expect such direct observation of the pathways of growth will contribute the understanding and controlling of solution synthesis of nanomaterials. ***This project is funded by LDRD of LBNL. We acknowledge the TEM facility support of National Center for Electron Microscopy (NCEM) in LBNL. NCEM is funded by the Director, Office of Science, Office of Basic Energy Sciences, Materials Science and Engineering Division of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
5:15 PM - D13.4
In Situ X-Ray Scattering Studies of Supercritical Nanoparticle Synthesis.
Christoffer Tyrsted 1 , Bo Iversen 1
1 Center for Materials Crystallography, Aarhus University, Aarhus Denmark
Show AbstractNanoparticles form a cornerstone of nanoscience and nanotechnology having their effectiveness in a variety of applications governed by the specific nanoparticle characteristics. Control of nanoparticle structure, size, size distribution, crystallinity and morphology are therefore key points in the synthesis of nanoparticles.[1]Supercritical synthesis offers a fast, one-step route for the production of nanomaterials utilising environmentally friendly reaction mediums such as water, ethanol or methanol. The procedure offers the possibility of synthesizing a large variety of inorganic nanoparticles with tuneable characteristics (size, morphology and crystal structure).[2]The main body of work leading to the understanding of the chemical processes involved in nanoparticle formation and growth, is based on characterisations of the products obtained after varying synthesis parameters (pressure, temperature, concentrations, pH etc.), i.e. ex situ investigations.[3] Even though these methods have provided invaluable knowledge, a complete understanding of the mechanisms involved during synthesis, however, remains elusive. So-called in situ studies are, therefore, required to probe the reactions as they occur. X-ray techniques are common characterization tools in the field of in situ studies, and may be used for a wide variety of in situ experiments including, small-angle scattering, diffraction, powder diffraction, total scattering, and absorption experiments. We have developed a range of unique in situ reactors capable of withstanding the high pressure and high temperature conditions of supercritical synthesis.[4] Here, in situ studies on the supercritical synthesis of yttria stabilized zirconia (YxZr1-xO2-x/2) and gadolinium doped ceria (GdxCe1-xO2-x/2) are presented. The studies reveal the changes in material characteristics (particle size/shape/distributions, crystallinity, atomic structure and more) throughout the synthesis to give a comprehensive description which may be used to direct syntheses on a larger scale. [1] G. A. Ozin and A. C. Arsenault, Nanochemistry: A Chemical Approach to Nanomaterials, Royal Society of Chemistry, 2005, p.[2] C. Aymonier et al., Journal of Supercritical Fluids 2006, 38, 242-251.[3] a) J. L. Mi et al., Acs Nano 2010, 4, 2523-2530;b) P. Hald et al., Journal of Solid State Chemistry 2006, 179, 2674-2680.[4] a) N. Lock et al., Angew. Chem. Intl. Ed. 2011, in press. b) K. M. Ø, Jensen et al., Crystal Growth & Design 2011, 11, 753–758. c) J. Mi. et al., Chem. Mater. 2011, 23, 1158–1165. d) C. Tyrsted et al., Chem. Mater. 2010, 22, 1814–1820. e) J. Becker et al., J. Appl. Crystallogr. 2010, 729–736. f) N. Lock et al., Chem. Eur. J. 2009, 15, 13381 – 13390. g) M. Bremholm et al., Angew Chem. Intl. Ed. 2009, 48, 4788-4791.
5:30 PM - D13.5
Controlled Synthesis of Nanoparticles of TiO2 and MnO2 by Precipitation in Aqueous Solution for the Control of the Properties.
Sophie Cassaignon 1 2 , Olivier Durupthy 1 2 , David Portehault 1 2 , Jean-Pierre Jolivet 1 2
1 LCMCP, UPMC, Paris France, 2 LCMCP, College de France, Paris France
Show AbstractTitanium dioxide is largely used in technological applications as a white pigment for paints or cosmetics, as a support in catalysis and as a photocatalyst. It is also a common material for photovoltaic cells. Manganese oxides have found applications in catalysis and energy storage. As for many other solids, nanosized TiO2 and MnO2 particles are of a particular interest because of their specifically size-related properties. Hence, many works have focussed on the synthesis nanoparticles. The uses and performances of a material for a given application are however strongly influenced by the crystalline structure, the morphology and the size of the particles. In addition, particles with varying mean size and narrow size distribution can be needed to study the surface effects over an extended range of surface/volume ratio. For metal oxide particles, the precipitation or coprecipitation of cations in aqueous solutions is an easy and cheap synthesis route. Various techniques consist in limiting the space available for the particle growth by precipitating ions in microemulsions, vesicles, polymer solutions or gels. Complexing agents are also often used but they mostly act on the morphology of the particles. Such methods raise difficulties in getting out particles free from polymer, surfactant or ligands, the adsorption of such species mostly inducing surface effects strongly influencing the behavior of particles. Actually, a careful control of the conditions of precipitation in aqueous medium, especially nature of the precursors, acidity and temperature, allow to control the crystal structure, the size and the morphology of particles. This presentation is focused on the synthesis of Titania and Manganese oxides polymorphs by hydrolysis of TiCl4 and/or TiCl3 and MnCl2 and/or MnO4- in water and on the influence of the synthesis parameters on the nature of the particles obtained. In addition we will discuss on the effect of the structure and the morphology on the properties, in particular in the photovoltaic devices and in lithium batteries.
5:45 PM - D13.6
Growth Dynamics of CdSe Quantum Dots Generated in Polar Polymers: A Kinetic Study.
Isabella Concina 1 , Marta Natile 2 , Giorgio Sberveglieri 1 , Alberto Vomiero 2 , Eugenio Tondello 1
1 Dept. Chemistry and Physics, Brescia University, CNR-IDASC SENSOR Lab, Brescia Italy, 2 , CNR-ISTM, INSTM & Department of Chemical Sciences, Padova University, Padova Italy
Show AbstractIncorporation of semiconductor quantum dots (QDs) in functional polymers is a field of great interest, since it should provide for flexible nanocomposites, with new optical and mechanical properties suitable for technical applications [1]-[8].In this study, CdSe QDs were directly generated inside biocompatible polymers, namely polyvinylpirrolidone (PVP), polyethyleneglycol (PEG) and polyvinylalcohol (PVA) [9]-[11], with the aim to investigate the skill of these media in both sustain the growth and stabilize the nanocrystals (NCs). Growth dynamics of the nanocomposites were studied, with particular emphasis on the kinetics and particles size evolution. A system without any stabilizer, but the native acetate molecules present on Cadmium precursor, was also considered.Kinetic curves were found to follow a sigmoidal trend in each case, thus indicating a self-catalytic pathway, whose rate strictly depended on the nature of the polymer, i.e. on the ability to effectively activate the Cadmium species present in mixture reaction.Size evolution of NCs was found to follow a two-step process, indicating two different stages of growth operating in the systems. At the very beginning particle growth is very fast and then slows down.6 There exists a critical diameter at which the fast process stops and the slow step starts working; the value of this diameter resulted very similar for all the systems, except the PEG-stabilised CdSe QDs, which showed the smallest value. All the nanocomposites were however keeping quite low both the size regime (<5 nm) and the size dispersion (full width at half maximum of emission feature <40 nm) [12].The medium-term stability of obtained materials has been also evaluated, being this feature critical for final applications. All the systems showed a shrinking of NCs, presenting an exponential decay over the time in optical density, while preserving both the size and size dispersion. Decay constants evaluation indicated PVP-stabilised CdSe QDs as the most stable system toward the shrinking process.1X. Michalet et al.,, Science, 2005, 28, 538-544.2I. L. Medintz et al., Nat. Mater., 2005, 4, 435-446.3R. C. Somers et al., Chem. Soc. Rev., 2007, 36, 579-591.4J. H. Bang and P. V. Kamat, ACS Nano 2009, 3, 1467-1476.5B. G. Ershov et al., J. Phys. Chem. B, 2000, 104, 6138–6142.6R. Tannenbaum et al., Macromolecules, 2005, 38, 4254-4259.7H. Zhang et al., Soft Matter, 2009, 5, 4113-4117.8J. Lee et al., Adv. Mat., 2000, 12, 1102-1105.9Y. E. Kirsh, Poly-N-vinylamides, 1998, Wiley, NY.10C. G. Shayne, Handbook of pharmaceutical biotechnology, 2007, Wiley, NY11J. Y. Chang, Biopolymers, PVA hydrogels, anionic polymerisation, nanocomposites, 2000, Springer.12X. Peng et al., J. Am. Chem. Soc., 1998, 120, 5343-5344.