Boosting the photocatalytic activity of ZnIn2S4-based photocatalyst for H2 evolution using porous ZnWO4 nanoflakelets as a cocatalyst

Abstract

ZnIn₂S₄ is considered one of most promising green catalysts for visible light driven photocatalytic H₂ generation, but it suffers from relatively low photocatalytic performance. Here, we for the first time report the design and preparation of an efficient ZnIn₂S₄-based catalyst using porous ZnWO₄ as cocatalyst (denoted ZIS/PZW). ZIS/PZW consists of flower-like microspheres composed of ZnIn₂S₄ nanosheets embedded with porous ZnWO₄ nanoflakelets. The as-synthesized ZIS/PZW showed excellent photocatalytic performance for H₂ generation with an optimal hydrogen production rate of 8.86 mmol g⁻¹ h⁻¹. Further investigation revealed that the porous ZnWO₄ cocatalyst could lead to the formation of dense contact sites with ZnIn₂S₄ nanosheets, thus benefiting electron migration. The hydrogen generation rate was found to be 2.15 times higher than that when solid ZnWO₄ nanoparticles acted as cocatalyst. Our work highlights the importance of finely designing cocatalysts and provides a new route for the further development of high-efficiency ZnIn₂S₄-based photocatalysts for H₂ generation.