Phase Effect of NixPy Hybridized with g-C₃N₄ for Photocatalytic Hydrogen Generation

The use of noble metal-free nickel phosphides (Ni x P y ) as suitable cocatalysts in photocatalytic hydrogen (H 2 ) generation has gained a lot of interest. In this paper, for the first time, three different crystalline phases of nickel phosphides, Ni 2 P, Ni 12 P 5, and Ni 3 P, were synthesized and then hybridized with g-C 3 N 4 to investigate the phase effect of Ni x P y on photocatalytic H 2 generation. It has been found that all three phases of Ni x P y work as effective cocatalysts for the enhancement of visible light H 2 generation with g-C 3 N 4 . The effective charge transfer between g-C 3 N 4 and Ni x P y, demonstrated by photoelectrochemical properties, photoluminescence, and time-resolved diffused reflectance, contributes to the enhanced photocatalytic H 2 generation performance. Interestingly, Ni 2 P/g-C 3 N 4 showed the highest photocatalytic activity among the three Ni x P y /g-C 3 N 4 . Ni x P y with a higher ratio of phosphorus (Ni 2 P) can accelerate charge transfer and provide more Ni–P bonds, leading to a preferable H 2 generation performance.