CoP co-catalyst modification ZnIn2S4 driving efficient H2 evolution under visible light

ZnIn2S4 (ZIS) limits photocatalytic hydrogen production activity by virtue of low visible light utilization and insufficient separation efficiency of photogenerated carriers. The metal phosphide CoP has been widely investigated as a valid co-catalyst for hydrogen generation due to its low cost compared to precious metals (Pt, Au and Ag). In this work, CoP was used as a co-catalyst and combined with ZIS to form an I − heterojunction, which significantly improved the separation of photogenerated carriers. The experimental finding from Transient photocurrent (TPR) indicates that a peak photocurrent density of approximately 5.5 μA/cm2 is achieved with a mass fraction of CoP stands at 4 %, surpassing ZIS by a factor of 11 (0.5 μA/cm2). At the same time, the Photoluminescence (PL) test results showed that CoP/ZnIn2S4-4 (CoP/ZIS-4) has the highest photogenerated carrier separation efficiency. Meanwhile, achieving the top rate of 4.24 mmol·g−1·h−1 for hydrogen production through photocatalysis is possible under visible light, a value that surpasses pure ZIS by 5.97 times (0.71 mmol·g−1·h−1). This work introduces an innovative approach to enhancing efficiency of co-catalysts while keeping costs low.