Synthesis and Characterization of the New Phase of Ferric Hydroxide Intercalated with Heteroanioninc Material

Iron oxyhydroxide is well known as the abundant clay mineral based on the Fe element, which plays a crucial role in maintaining the biogeochemical cycle and ecosystem. From different point of view, it also has been gaining attention from metallurgy, water purification, energy storage, and many other fields [1]. Ferrihydrite, green rust, and ferric oxyhydroxide polymorphs such as goethite, akaganeite, lepidocrocite, feroxyhyte are naturally occurred iron oxyhrdoxides. These materials are metastable form in the formation of relatively stable Fe-O iron oxides that act as a bridge to intricate crystallization chain of iron oxides. Therefore, the synthesis of new iron oxyhydroxide discovered a new pathway of crystallization of iron oxides.<br/>The particle attachment-based crystallization mode is well known method to synthesize the iron oxyhydroxides which building units grow into colloidal assembly to form the final structure. It is also a widely accepted growth model the explains the formation of inorganic-organic composites such as metal organic frameworks (MOFs), layered double hydroxides (LDHs) [2]. Heteroaninoic material grafted on the inorganic building units is used to control the intermolecular interaction of the synthetic process and arranges the assembly of the building units [3]. In this study, we synthesized and characterized the new form of iron oxyhydroxide by intercalating the functional heteroanionic material. The ordered stacking of 2D sheet of inorganic with heteroionic material shows the unknown crystal structure, that is different from the known phases such as lepidocrocite and green rust. We suggest that the heteroanioinc material is involved in the FeO6 octahedron which consists of the 2D sheets via covalent bonds to induce the distortion and lamination of the crystal arrangement.<br/>Reference<br/>[1]. J.-H. Kim et al, J. Mater. Chem. A 6, 12 (2018)<br/>[2]. X Duan et al, Nature 567 321 (2019)<br/>[3]. H Kang et al, Appl Clay Sci 112, 32 (2015)