Cu–S Bonds as an Atomic-Level Transfer Channel to Achieve Photocatalytic CO 2 Reduction to CO on Cu-Substituted ZnIn 2 S 4

Due to the intrinsic chemically inert CO 2 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 CO 2 reduction. Renewing the electronic structure of adsorbed CO 2 on the catalyst surface through a rational catalyst design is crucial to achieving performance improvement. Herein, we prepared ZnIn 2 S 4 and Cu-substituted ZnIn 2 S 4 containing both Lewis acid and Lewis base sites as a model system for investigating the activation of CO 2 by M–S chemical bonds (M represents a metal site). The Cu–S chemical bond can effectively activate CO 2 as a vital electron channel and lower the Gibbs free energy for generating the essential intermediate *COOH. Besides, the Cu 0.7 -ZnIn 2 S 4 sample displays 74.8% selectivity for reducing CO 2 to CO with a rate of 47.2 μmol g –1 h –1, roughly 7.14 times that of ZnIn 2 S 4 .