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

Solar-driven photocatalytic CO ₂ 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 (C ₂ ) 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-N ₄ and Mo-N ₄ active sites have been designed and integrated in CuPor-POP-Mo as cascade dual metal sites for efficient photocatalytic reduction of CO ₂ to ethane (C ₂ H ₆ ) for the first time. Significantly, an excel-lent C ₂ H ₆ 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 C ₂ H ₆ production by using porous polymer catalysts. In-situ spectral characterizations and DFT calculations indicate that unlike the electrocatalytic CO ₂ to C ₂ 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 CO ₂ photoreduction to C ₂ H ₆ . Our work provides new insights into the rational design of photocatalysts for the effective production of C ₂ and C ₂₊ products from CO ₂ .