Construction of Co3(PO4)2/ZnIn2S4 type-II heterojunction for photocatalytic hydrogen production

ZnIn 2 S 4 is a highly promising photocatalyst, but its rapid carrier recombination remains the core bottleneck. Constructing band-matched heterojunctions to promote charge separation is currently the most effective strategy to address this issue. Herein, a Co 3 (PO 4 ) 2 /ZnIn 2 S 4 (CPO/ZIS) type-II heterojunction photocatalytic system is designed. The intimate coupling between CPO and ZIS is achieved via electrostatic self-assembly. Studies show that this system follows a type-II charge transfer mechanism, and owing to the strong affinity of phosphate groups for protons in aqueous solution and the electron-trapping function of cobalt active centers, the hydrogen production efficiency is synergistically enhanced. The optimal 10-CPO/ZIS composite achieves a HER of 8.87 mmol g −1  h −1 , which is 8.53 times that of pristine ZIS, and also exhibits excellent photocorrosion resistance.