Enhancing photocatalytic performance of metal-organic frameworks for CO2 reduction by a bimetallic strategy

Metal-organic frameworks (MOFs) as a type of crystalline heterogeneous catalysts have shown potential application in photocatalytic CO2 reduction. However, MOF catalysts with high efficiency and selectivity are still in pursuit. Herein, by a bimetallic strategy, the catalytic performance of a Co-MOF for photocatalytic CO2 reduction was enhanced. Specifically, the Co-MOF based on 4,5-dicarboxylic acid (H3IDC) and 4,4ʹ-bipydine (4,4ʹ-bpy) can catalyze CO2 reduction to CO, with high efficiency but relatively low selectivity. After replacement of 2/3 Co(II) with Ni(II) within Co-MOF, the resulted isostructural Co1Ni2-MOF not only retains high efficiency for photocatalytic CO2 reduction, but also shows enhanced CO selectivity. The CO evolution rate reaches 1160 µmol g−1 h−1 and the CO selectivity reaches as high as 94.6%. The enhanced photocatalytic CO2 reduction performance is supported by theoretical calculation results. This case demonstrates that bimetallic strategy is an effective mean to optimize the catalytic performance of MOF catalysts for photochemical CO2 reduction.