A Molecular Z‐Scheme Artificial Photosynthetic System Under the Bias‐Free Condition for CO<sub>2</sub> Reduction Coupled with Two‐electron Water Oxidation: Photocatalytic Production of CO/HCOOH and H<sub>2</sub>O<sub>2</sub>
Fazalurahman Kuttassery, Yutaka Ohsaki, Arun Thomas, Ryutaro Kamata, Yosuke Ebato, Hiromu Kumagai, Ryosuke Nakazato, Abin Sebastian, Siby Mathew, Hiroshi Tachibana, Osamu Ishitani, Haruo Inoue
Abstract
Abstract Bio‐inspired molecular‐engineered systems have been extensively investigated for the half‐reactions of H 2 O oxidation or CO 2 reduction with sacrificial electron donors/acceptors. However, there has yet to be reported a device for dye‐sensitized molecular photoanodes coupled with molecular photocathodes in an aqueous solution without the use of sacrificial reagents. Herein, we will report the integration of Sn IV ‐ or Al III ‐tetrapyridylporphyrin (SnTPyP or AlTPyP) decorated tin oxide particles (SnTPyP/SnO 2 or AlTPyP/SnO 2 ) photoanode with the dye‐sensitized molecular photocathode on nickel oxide particles containing [Ru(diimine) 3 ] 2+ as the light‐harvesting unit and [Ru(diimine)(CO) 2 Cl 2 ] as the catalyst unit covalently connected and fixed within poly‐pyrrole layer (RuCAT‐RuC 2 ‐ PolyPyr ‐PRu/NiO). The simultaneous irradiation of the two photoelectrodes with visible light resulted in H 2 O 2 on the anode and CO, HCOOH, and H 2 on the cathode with high Faradaic efficiencies in purely aqueous conditions without any applied bias is the first example of artificial photosynthesis with only two‐electron redox reactions.