Phase Effect of NiP Hybridized with g-CN for Photocatalytic Hydrogen Generation.

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