Construction of a hierarchical CoP@ZnIn2S4 heterojunction for photocatalytic hydrogen evolution

Abstract

To relieve the present energy scarcity and environmental challenges, hydrogen formation via water decomposition utilizing sunlight is desirable. However, due to poor charge separation and low hydrogen production efficiency, conventional semiconductor photocatalysts are limited in practical applications. Herein, by introducing a spatial decoupling strategy, a core–shell CoP@ZnIn₂S₄ heterojunction photocatalyst is built through in situ formation of two-dimensional ZnIn₂S₄ (ZIS) nanosheets on a spiky CoP surface, achieving effective separation of the redox sites, resulting in a substantial enhancement of photocatalytic hydrogen formation efficiency. Notably, the optimized 5-CoP@ZIS photocatalyst exhibits a hydrogen production rate of 14.98 mmol g⁻¹ h⁻¹ with full solar spectrum illumination, which is 6.3-fold higher than the individual ZIS. These results exhibit that the increased efficiency is explained by the creation of the CoP@ZIS core–shell heterostructure, which strongly prevents the self-assembly and aggregation of the ZIS nanosheets, and offers enhanced light absorption and an abundance of reaction sites. The close interfacial contact facilitates the light-induced electron separation and transfer from ZIS to CoP, which synergistically yields an efficient hydrogen production performance. This work offers a highly effective method for the fabrication of powerful photocatalysts to realize light energy conversion.