Electro-reduced copper on polymeric C3N4 for photocatalytic reduction of CO2

Coupling light absorber with an efficient cocatalyst is the most common way to fabricate composite photocatalyst . The light absorber supplies electrons and holes, while the cocatalyst domains chemical reactions. Inspired by the results from electrochemical CO 2 reduction, Cu-based materials are the most promising cocatalysts for photocatalytic CO 2 reduction. However, oxide-derived copper (OD-Cu) hasn't been introduced into photocatalytic systems yet, due to easily undergoing valence changes once exposed to air. Herein, we find that OD-Cu could be decorated on photocatalyst, polymeric C 3 N 4 (PCN), by a self-designed in-situ electroreduction method. The as-prepared OD-Cu/PCN presents better visible light absorption than the one without in-situ electroreduction and prefers multi-carbon products. According to CO 2 RR measurements, the highest selectivity to C 2 H 5 OH is 58%. Density functional theory calculation further indicates that the unique structure between OD-Cu and PCN leads to a low energy barrier of C–C coupling due to the enhanced *CO dimerization and thus promotes the production of C 2 H 5 OH. Moreover, this optimized sample achieves a solar-to-fuel efficiency, of up to 0.94%, which is 1.69 times the pristine PCN.