121st General Meeting of the KCS

Type Symposium
Area Light Driven Carbon Recycling: Photocatalytic Carbon Dioxide Reduction
Room No. Room 401
Time THU 17:10-:
Code IND-4
Subject Photosynthetic Energy Conversion: Molecular Metal Catalysts to Photoelectrochemical Cells
Authors Jinheung Kim
Chemistry Department of Nano-Science, Ewha Womans University, Korea
Abstract Artificial photosynthesis can convert the solar energy into the solar fuel such as hydrogen by driving high-energy chemical reactions. Dye-sensitized photoelectrosynthesis cell is an integrated photoelectrochemical system of high band gap semiconductor such as the TiO2 and molecular assemblies with chromophore for light absorption and molecular metal catalyst. A molecular chromophore adsorbed on semiconductor electrode absorbs visible light and injects an electron into the conduction band. To fabricate artificial photosynthetic systems, efficient visible light-absorbing materials have to link reduction and oxidation catalysts for an efficient energy flow. As a step toward this goal of an NADH regeneration system and enzymatic production of solar fuels from CO2, we studied the synthesis of a new conjugated polydiacetylene polymer that is covalently connected with [Ru(phen-NH2)(bpy)2]2+. The [(bpy)2Ru(phen)]-polydiacetylene absorbed a wide range of visible light because of the presence of two chromophores, the Ru complex and polydiacetylene. The electron transfer from the photoexcited [Ru(phen)(bpy)2]2+ to the polydiacetylene backbone was observed. In a visible light-driven photocatalytic NAD+ reduction by (cyclopentadienyl)Rh(bpy)(H2O)2+ with [(bpy)2Ru(phen)]-polydiacetylene, NADH was regenerated. The consecutive carbon dioxide reduction coupled with formate dehydrogenase was carried out to utilize the photoregenerated NADH catalytically. PtNPs have also been reported to act as a photosensitizer as well as a catalyst during photocatalytic regeneration of NADH. The use of cobaloxime complexes is also presented in an electrochemical system for NADH regeneration from aqueous protons in buffer.
E-mail jinheung@ewha.ac.kr