Room-temperature co-precipitation of nickel phosphate-coated Zn0.4Cd0.6S nanorods for enhanced photocatalytic H₂ evolution in water splitting

To enhance the hydrogen production performance and photo-corrosion resistance of ZnS and CdS based photocatalysts without relying on noble metals such as platinum, ruthenium, or gold, this study optimizes the molar ratio between Cd and Zn in Zn_xCd_1-xS solid solutions. The resulting Zn_0.4Cd_0.6S nanorod-shaped solid solutions exhibit superior visible-light photocatalytic activity. A non-precious metal Ni₃(PO₄)₂ nano-thin layer is uniformly deposited onto the surface of the Zn_0.4Cd_0.6S solid solution via a room-temperature chemical co-precipitation method. This modification not only prevents oxidative photo-corrosion but also facilitates the oxidation and reduction of water during the photocatalytic surface process, significantly enhancing both the stability and hydrogen production performance of the composite catalyst. Experimental results demonstrate that the performance improvement of Zn_0.4Cd_0.6S by the Ni₃(PO₄)₂ cocatalyst is markedly greater than that achieved with the traditional Pt cocatalyst. The maximum hydrogen production rate of the composite catalyst reaches 119.72 mmol·g⁻¹·h⁻¹, with an accumulated hydrogen production of 340.33 mmol·g⁻¹ after 3 hours. After 25 hours of photocatalytic cycling experiments, the hydrogen production rate remains at 95.95 mmol·g⁻¹·h⁻¹, approximately 80.14 % of the initial rate. The apparent quantum yield of Z4C6S-5NPO attains 61.8 %, with high value in ZnCdS-based photocatalysts. These results are promising and offer valuable insights for the development of low-cost, highly stable, and efficient composite photocatalysts.