Facile synthesis of ZIF-derived ZnS/ZnIn2S4 heterojunction and enhanced photocatalytic hydrogen evolution

A facile synthetic route by using rhombic dodecahedral zeolitic imidazolate framework-8 (ZIF-8) as the structure template is devoted to fabricating ZnS/ZnIn2S4 hybrid heterojunction, which combined the sulfurization of ZIF-8 and in-situ precipitation of ZnIn2S4 in one pot and produced the compact heterostructure. The resulting ZnS nanoparticles sized in about 100 nm were uniformly dispersed in the folds of flower like ZnIn2S4, which structure is beneficial in the charge transfer at the heterointerface. The addition quantities of ZIF-8 are varied to find an optimum ratio for two components to get the best photocatalytic activity. In the photocatalytic hydrogen generation irradiated by simulated solar light, all the ZnS/ZnIn2S4 hybrid photocatalysts displayed improved hydrogen production rates compared to single ZnS or ZnIn2S4, and the best hydrogen production rate of 453.4 μmol h−1 g−1 is obtained by ZnS/ZIS-20, which value is approximately 4-times higher than that of single ZnIn2S4. The electrochemical properties of ZnS/ZnIn2S4 hybrid photocatalysts were measured to explore the charge transfer mode at the interface, and the band structure and the enhanced photocatalytic hydrogen generation mechanism have been proposed. The excellent recycling hydrogen production indicated the prospective applications of this kind of ZIFs-derived metal sulfides in the photocatalytic reactions.