Insight into the function of noble-metal free Cu3P decorated Zn0.5Cd0.5S for enhanced photocatalytic hydrogen evolution under visible light irradiation-- mechanism for continuous increasing activity

Abstract

The development of low-cost photocatalysts for highly efficient and durable photocatalytic H2 evolution under visible light is of great challenge. In present study, a Z-scheme Cu3P/Zn0.5Cd0.5S is fabricated via in-situ phosphidation method for efficient visible-light-driven H2 evolution. The wide light absorption property of Cu3P enhances the visible light absorption of Cu3P/Zn0.5Cd0.5S. The electrical conductivity of metallic Cu3P and the Z-scheme constructure of Cu3P/Zn0.5Cd0.5S accelerate electron transport rate. The Cu3P/Zn0.5Cd0.5S catalyst achieves highest hydrogen evolution rate of 2.7 mmol g−1 h−1, which is 3.1 folds higher than that of pristine Zn0.5Cd0.5S. More interestingly, the Cu3P/Zn0.5Cd0.5S exhibited increasing H2 production during reaction. The further reduction of PO33−→P&− and the further formation of Cu3P is determined to be the key reason for increasing activity. Besides, Cu3P/Zn0.5Cd0.5S prepared by in-situ phosphidation method shows much better catalyst property and performance than that prepared by afterwards mixing method, and the possible reasons for such difference is proposed in present study.