Insights into the Interaction Effect of CuSA-ZnS for Enhancing the Photocatalytic Hydrogen Evolution

The effect of metal–support interactions on metal single-atom anchoring and photocatalytic mechanism needs further study in metal sulfide photocatalysts. Herein, via the strong interaction between Cu2+ and unsaturated atoms as well as the spatial confinement effect of vacancies, the Cu single atoms (CuSAs) were constructed on the surface of ZnS. The anchored CuSAs and some intrinsic Zn atoms on the ZnS surface can transform into high active Znδ+ and Cuδ+ (1 < δ < 2) under irradiation, which significantly improves the photocatalytic hydrogen evolution performance. Combined with density functional theory, the interaction between CuSAs and ZnS can regulate the electronic structures of d-band and p-band, which optimizes the adsorption of H-intermediates and promotes the excitation and transfer of photopromoted electrons. Particularly, the change of p-band electrons leads to electron redistribution, which activates the intrinsic Zn atoms adjacent to the Cu1-at-VZn configuration under the irradiation. The activated Znδ+ and Cuδ+ become the adsorption sites of H-intermediates and return to the initial state after photopromoted electrons transferred to them reduce H-intermediates to H2. This study proposes an insightful exposition for the photocatalytic micro mechanism of metal single-atom metal sulfides and provides ideas for the design and modification of efficient photocatalysts.