Conductive 2D Metal-Organic Frameworks for Chemical Sensor Applications

Metal-organic frameworks (MOFs) are materials formed by the combination of metal nodes and organic linkers. They possess a large surface area and high porosity, making them promising materials for chemical sensing applications. Several MOFs have been synthesized and utilized as chemical sensing layers in combination with other sensing materials such as metal oxides, as demonstrated in our previous studies [1-4] However, intrinsic 3D MOFs typically exhibit insulating properties, which limits their application in electrochemical sensing materials. In contrast, electrically conductive 2D MOFs have recently gained attention for chemiresistive-type gas sensor applications. These materials possess intrinsic electrical conductivity and show redox-reactive properties with gaseous analytes.<br/>The presentation will highlight recent progress in the development of conductive 2D MOFs and their application in chemiresistive-type gas sensors. Various electrically conductive 2D MOFs were prepared by combining metal nodes (Cu²⁺, Ni²⁺, and Co²⁺) with an organic linker (hexahydroxytriphenylene, HHTP). The result showed that the 2D Cu₃(HHTP)₂ MOF film exhibited high sensitivity toward hydrogen sulfide and toluene at room temperature. To gain insights into the fundamental sensing mechanism, an in-situ spectroscopy analysis technique was established. This technique involved monitoring surface adsorbed species and by-products after chemical reactions using Raman spectroscopy and gas chromatography-mass spectroscopy (GC-MS), respectively. Through these investigations, a better understanding of the fundamental sensing mechanisms of 2D MOFs was obtained, paving the way for the development of high-performance chemical sensors for environmental monitoring and healthcare applications.<br/> <br/><b>References</b><br/>[1] <u>Seon-Jin Choi</u>, Hack-Jong Choi, Won-Tae Koo, Daihong Huh, Heon Lee*, and Il-Doo Kim*, <i>ACS Applied Materials & Interfaces</i>, Vol. 9, No. 46, pp. 40593−40603, 2017.<br/>[2] Won-Tae Koo, Ji-Soo Jang, <u>Seon-Jin Choi</u>, Hee-Jin Cho, and Il-Doo Kim*, <i>ACS Applied Materials & Interfaces</i>, Vol. 9, pp. 18069-18077, 2017.<br/>[3] Won-Tae Koo, <u>Seon-Jin Choi</u>, Ji-Soo Jang, and Il-Doo Kim*, <i>Scientific Reports</i>, Vol. 7, No. 45074, 2017.<br/>[4] Won-Tae Koo, <u>Seon-Jin Choi</u>, Sang-Joon Kim, Ji-Soo Jang, Harry L. Tuller, and Il-Doo Kim*, <i>Journal of the American Chemical Society (JACS)</i>, Vol. 138, pp. 13431-13437, 2016.