Construction of core–shell CoSe2/ZnIn2S4 heterostructures for efficient visible-light-driven photocatalytic hydrogen evolution

Abstract

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 CoSe₂/ZnIn₂S₄ heterostructures were successfully fabricated via in situ growth of ZnIn₂S₄ ultrathin nanosheets on spherical CoSe₂. Without any noble metal co-catalysts, the as-prepared CoSe₂/ZnIn₂S₄ composite achieved attractive photocatalytic hydrogen evolution activity under visible light illumination. Optimal CoSe₂/ZnIn₂S₄ achieved a hydrogen evolution rate of 2199 μmol g⁻¹ h⁻¹, which was 7 times higher than that of pristine ZnIn₂S₄ and even exceeded that of ZnIn₂S₄ loaded with platinum. In this distinctive core–shell heterostructure, the presence of CoSe₂ could considerably improve the ability to harvest light, quicken the charge transfer kinetics, and avoid the agglomeration of ZnIn₂S₄ nanosheets. Meanwhile, the experimental results demonstrated that the strong interaction between CoSe₂ and ZnIn₂S₄ 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.