Fabrication of a ternary NiS/ZnIn2S4/g-C3N4 photocatalyst with dual charge transfer channels towards efficient H2 evolution.

ABSTRACT

As a renewable green energy, hydrogen has received widespread attention due to its huge potential in solving energy shortages and environment pollution. In this paper, a one-step solvothermal method was applied to grow ultra-thin g-C3N4 (UCN) nanosheets and NiS nanoparticles on the surface of ZnIn2S4 (ZIS). A ternary NiS/ZnIn2S4/ultra-thin-g-C3N4 composite material with dual high-speed charge transfer channels was constructed for the advancement of the photocatalytic H2 generation. The optimal ternary catalyst 1.5wt.%NiS/ZnIn2S4/ultra-thin-g-C3N4 (NiS/ZIS/UCN) achieved a H2 evolution yield reached to 5.02 mmolg-1h-1, which was 5.23 times superior than that of pristine ZnIn2S4 (0.96 mmolg-1h-1) and even outperform than that of the best precious metal modified 3.0 wt%Pt/ZnIn2S4 (4.08 mmolg-1h-1). The AQY at 420 nm could be achieved as high as 30.5%. The increased photocatalytic performance of NiS/ZIS/UCN could be ascribed to the type-I heterojunctions between intimated ZIS and UCN. In addition, NiS co-catalyst with large quantity of H2 evolution sites, could result in efficient photo-induced charges separation and migration. Furthermore, the NiS/ZIS/UCN composite exhibited excellent H2 evolution stability and recyclability. This work would also offer a reference for the design and synthesis of ternary co-catalyst with heterojunction composite for green energy conversion.