S‐Scheme Heterojunction and Defect Site Engineering on CuxIn₅S₈−Cu2‐ySe for Highly Efficient Photoreduction of CO₂ to methanol

The conversion and utilization of CO 2 is imminent. Herein, the Cu x In 5 S 8 −Cu y Se S‐scheme heterojunction catalyst was successfully synthesized by the MOF‐derived method and the strategy of surface hydrogenation. In a photocatalytic performance test, Cu 1.5 In 4.5 S 7.5 −Cu 1.45 Se has excellent catalytic activity, and the production rate of methanol is 5.250 umol g −1 h −1 , and the methanol selectivity is about 100 %. In addition, through DFT calculation and in situ FT‐IR, a new mechanism for the catalytic reduction of CO 2 to methanol by bimetallic sites or variable valence metal sites is revealed, which opens up a new strategy to conversion of CO 2 into energy fuel. This research couples charge accumulation centers, active sites and adsorption sites on the exposed active interface to enhance the visible light‐driven photocatalytic performance of the catalyst through defect engineering, morphology engineering and heterojunction engineering, which provides a promising approach to facilitate the selective photocatalytic reduction of CO 2 to methanol.