Construction of core-shell CoSe 2 /ZnIn 2 S 4 heterostructures for efficient visible-light-driven photocatalytic hydrogen evolution.

The use of photocatalysts based on semiconductor heterostructures for hydrogen evolution is a prospective tactic for converting solar energy. Herein, visible-light-responsive three-dimensional core-shell CoSe 2 /ZnIn 2 S 4 heterostructures were successfully fabricated via in situ growth of ZnIn 2 S 4 ultrathin nanosheets on spherical CoSe 2 . Without any noble metal co-catalysts, the as-prepared CoSe 2 /ZnIn 2 S 4 composite achieved attractive photocatalytic hydrogen evolution activity under visible light illumination. Optimal CoSe 2 /ZnIn 2 S 4 achieved a hydrogen evolution rate of 2199 μmol g -1 h -1 , which was 7 times higher than that of pristine ZnIn 2 S 4 and even exceeded that of ZnIn 2 S 4 loaded with platinum. In this distinctive core-shell heterostructure, the presence of CoSe 2 could considerably improve the ability to harvest light, quicken the charge transfer kinetics, and avoid the agglomeration of ZnIn 2 S 4 nanosheets. Meanwhile, the experimental results demonstrated that the strong interaction between CoSe 2 and ZnIn 2 S 4 at the compact interface could appropriately boost the photogenerated electron-hole pair migration and relieve charge recombination, thus improving photocatalytic hydrogen evolution activity. This work has bright prospects in constructing noble-metal-free core-shell heterostructures for solar energy conversion.