Boosting thermo-photocatalytic CO conversion activity by using photosynthesis-inspired electron-proton-transfer mediators.

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