Cooperative effects of zinc–nickel sulfides as a dual cocatalyst for the enhanced photocatalytic hydrogen evolution activity of g-C3N4

Abstract

ZnS−NiS2/g-C3N4 ternary composites were synthesized via a thermal polymerization and post co-deposition−sulfidation method. The decoration of g-C3N4 layers with ZnS−NiS2 nanoparticles extended visible light absorption and promoted the separation and transfer of photo-generated charge carriers. The photocatalytic performance of the ZnS−NiS2/g-C3N4 composites was evaluated by the visible-light-driven hydrogen evolution. Briefly, compared to g-C3N4, ZnS/g-C3N4, and NiS2/g-C3N4, the hydrogen evolution rate on ZnS−NiS2/CN(0.4) was separately increased by 31, 31, and 1 times, highlighting the synergistic effect of ZnS and NiS2. The interface between ZnS and g-C3N4 modified the charge separation and transfer process. Meanwhile, NiS2 with a Pt-like behavior acted as an electron acceptor to facilitate transfer photoelectrons and to provide active sites for proton reduction. This work will offer new insight into improving g-C3N4-based photocatalysts with mixed metal sulfides for efficient hydrogen evolution.