Self-doped zinc-mediated ZnIn2S4 microflowers towards optimized visible-light photocatalytic hydrogen production

Doping is a favorable strategy for modifying the performance of ZnIn2S4 (ZIS). However, the doped heteroatoms are prone to be the sites of carrier complexation. According to the coordination structure and the bond order relationship in hexagonal ZIS, we synthesized Zn self-doped ZIS as an efficient hydrogen evolution reaction (HER) photocatalyst by one-step hydrothermal method. By adjusting the content of Zn in the reaction precursor, the excess Zn competes with In and S to form a tetrahedral coordination structure. The doping of Zn in the In -S tetrahedron makes the conduction band shift negatively, which is conducive to the redox reaction. Moreover, the transfer rate of electrons and holes is accelerated, which is beneficial to inhibit the recombination of electronhole pairs. The optimized Zn-doped ZIS exhibits enhanced HER efficiency of 10.8 mmol/g/h under visible light, which is 2.9 times higher than that of the pristine ZIS.