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 photo catalytic hydrogen (H-2) 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 H-2 generation. It has been found that all three phases of NixPy work as effective cocatalysts for the enhancement of visible light H-2 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 H-2 generation performance. Interestingly, Ni2P/g-C3N4 showed the highest photocatalytic activity among the three NixPy/gC(3)N(4). NixPy with a higher ratio of phosphorus (Ni2P) can accelerate charge transfer and provide more Ni-P bonds, leading to a preferable H-2 generation performance.