Cu-S Bonds as an Atomic-Level Transfer Channel to Achieve Photocatalytic CO2 Reduction to CO on Cu-Substituted ZnIn2S4

Due to the intrinsic chemically inert CO2 with the dissociation energy of C=O bond as high as 750 kJ mol(-1), low efficiency and selectivity have become the most significant restraints for the practical application of photocatalytic CO2 reduction. Renewing the electronic structure of adsorbed CO2 on the catalyst surface through a rational catalyst design is crucial to achieving performance improvement. Herein, we prepared ZnIn2S4 and Cu-substituted ZnIn2S4 containing both Lewis acid and Lewis base sites as a model system for investigating the activation of CO2 by M-S chemical bonds (M represents a metal site). The Cu-S chemical bond can effectively activate CO2 as a vital electron channel and lower the Gibbs free energy for generating the essential intermediate *COOH. Besides, the Cu-0.7-ZnIn2S4 sample displays 4.8 degrees 6 selectivity for reducing CO2 to CO with a rate of 47.2 mu mol g(-1) h(-1), roughly 7.14 times that of ZnIn2S4.