Multi-enzyme reaction inspired cascade photocatalysis for solar-driven CO2 reduction to ethane

Abstract Solar-driven photocatalytic CO2 conversion into value-added chemicals and fuels is an emerging solution to the challenges of traditional energy and environmental/climate concerns. However, photocatalytic synthesis of two-carbon (C2) compounds is quite challenging due to the high activation barrier of C-C coupling reaction and low content of intermediates. Herein, inspired by the tandem synthesis in multi-enzyme reactions, Cu-N4 and Mo-N4 active sites have been designed and integrated in CuPor-POP-Mo as cascade dual metal sites for efficient photocatalytic reduction of CO2 to ethane (C2H6) for the first time. Significantly, an excel-lent C2H6 production rate of 472.5 µmol g− 1 h− 1 and a high product selectivity of 87.5% (electron selectivity ~ 97.5%) have been achieved, which are the record high values in photocatalytic C2H6 production by using porous polymer catalysts. In-situ spectral characterizations and DFT calculations indicate that unlike the electrocatalytic CO2 to C2 products reported previously, the Cu site mainly catalyzes *CO production, and the Mo site triggers the C-C coupling reaction between *CO intermediates, thus Cu and Mo sites synergistically boost CO2 photoreduction to C2H6. Our work provides new insights into the rational design of photocatalysts for the effective production of C2 and C2+ products from CO2.