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

The use of noble metal-free nickel phosphides (NixPy) as suitable cocatalysts in photocatalytic hydrogen (H2) generation has gained a lot of interest. In this paper, for the first time, three different crystalline phases of nickel phosphides, Ni2P, Ni12P5, and Ni3P, were synthesized and then hybridized with g-C3N4 to investigate the phase effect of NixPy on photocatalytic H2 generation. It has been found that all three phases of NixPy work as effective cocatalysts for the enhancement of visible light H2 generation with g-C3N4. The effective charge transfer between g-C3N4 and NixPy, demonstrated by photoelectrochemical properties, photoluminescence, and time-resolved diffused reflectance, contributes to the enhanced photocatalytic H2 generation performance. Interestingly, Ni2P/g-C3N4 showed the highest photocatalytic activity among the three NixPy/g-C3N4. NixPy with a higher ratio of phosphorus (Ni2P) can accelerate charge transfer and provide more Ni-P bonds, leading to a preferable H2 generation performance.