Strong interfacial coupling for NiS thin layer covered CdS nanorods with highly efficient photocatalytic hydrogen production

Abstract

The construction of heterojunctions is beneficial to improve the separation efficiency of photogenerated electron–hole pairs, so as to enhance the activity of photocatalysts. Herein, NiS thin layer covered CdS nanorods (NiS/CdS) were synthesized by a two-step hydrothermal approach. Under the irradiation of visible light, the optimal NiS/CdS covered heterojunctions showed high photocatalytic stability and excellent hydrogen evolution rate up to 401.7 mmol g⁻¹ h⁻¹, which is higher than that of most CdS-based photocatalysts. The apparent quantum efficiency of NiS/CdS at 420 nm was 1.5%. The formation of NiS/CdS heterojunctions with large intimate contact area leads to strong interfacial coupling between NiS thin layers and CdS nanorods. This promotes the separation and migration of photoinduced electron–hole pairs and provides more active sites for redox reactions, thus improving the activity of photocatalysts. This work presents new ideas for the design of high-performance photocatalysts for H₂ production.