Boosting thermo-photocatalytic CO2 conversion activity by using photosynthesis-inspired electron-proton-transfer mediators
Yingxuan Li, Danping Hui, Yuqing Sun, Ying Wang, Zhijian Wu, Chuanyi Wang, Jincai Zhao
Abstract
Abstract Natural photosynthesis proceeded by sequential water splitting and CO 2 reduction reactions is an efficient strategy for CO 2 conversion. Here, mimicking photosynthesis to boost CO 2 -to-CO conversion is achieved by using plasmonic Bi as an electron-proton-transfer mediator. Electroreduction of H 2 O with a Bi electrode simultaneously produces O 2 and hydrogen-stored Bi (Bi-H x ). The obtained Bi-H x is subsequently used to generate electron-proton pairs under light irradiation to reduce CO 2 to CO; meanwhile, Bi-H x recovers to Bi, completing the catalytic cycle. This two-step strategy avoids O 2 separation and enables a CO production efficiency of 283.8 μmol g −1 h −1 without sacrificial reagents and cocatalysts, which is 9 times that on pristine Bi in H 2 gas. Theoretical/experimental studies confirm that such excellent activity is attributed to the formed Bi-H x intermediate that improves charge separation and reduces reaction barriers in CO 2 reduction.