Fabrication of Sulfur Defect Rich ZnIn2S4/SnSe2 Photocatalyst with Ohmic Junction for Efficient Water to Hydrogen Energy Conversion

The development of a noble-metal-free cocatalyst is of great significance for boosting photocatalytic H-2 evolution performance. Herein, SnSe2 is developed as a cocatalyst to in situ attachment on the surface of sulfur defect rich ZnIn2S4 (Vs-ZIS) via a simple hydrothermal method. Owing to the intimate atomic-level interface and the different work function between Vs-ZIS and SnSe2, a particular Ohmic junction with internal electric field is formed in Vs-ZIS/SnSe2, which facilitates the electrons in Vs-ZIS transfer to SnSe2 and participate in H-2 evolution reaction rapidly. Moreover, the abundant S vacancies also benefit the separation of photocarriers in Vs-ZIS/SnSe2. The optimized Vs-ZIS/SnSe2 photocatalyst performs a high H-2 evolution rate of 29.34 mmol h(-1) g(-1) under visible light (lambda > 420 nm) and an apparent quantum efficiency of 12.25% at 420 nm. Herein, constructive model on developing effective cocatalyst is afforded, and expediting photocarriers transfer through interfacial modulating.

Automated summary

The development of noble-metal-free cocatalyst is crucial for enhancing photocatalytic H-2 evolution performance. In this study, SnSe2 is used as a cocatalyst attached to the surface of sulfur defect-rich ZnIn2S4 via a hydrothermal method. The resulting Vs-ZIS/SnSe2 photocatalyst exhibits high H-2 evolution rate and apparent quantum efficiency under visible light.