Alkene Epoxidation with Water by Confined Active Co Sites on BiVO4 Photoanodes under Visible Light.

Heterogeneous photoelectrocatalysis systems have recently seen significant growth in organic transformations, but are limited by the inherent physicochemical properties of electrode materials. To enhance selectivity in these processes, we propose an innovative advancement in the rational design of photoanodes. Specifically, we incorporated cobalt porphyrin co-catalysts with confined Co sites onto bismuth vanadate films as a photoanode. This photoanode significantly enhances the efficacy of styrene epoxidation, achieving selectivity and conversion rates of 90% and 99%, respectively. Notably, the reaction utilizes water as the sole oxygen source, operates at room temperature, and is easily scalable for gram-scale synthesis. The developed photoanode demonstrates robust performance across various alkene substrates. Operando characterizations reveal that during the epoxidation reaction, the confined Co sites within the porphyrin structure catalyze the oxidation of H2O to form Co-O*, serving as critical intermediates that facilitate cyclization reactions via one-electron processes. This study introduces an innovative heterogeneous PEC strategy with customizable active sites tailored for selective catalytic organic transformations.