Porous Ni5P4 as a promising cocatalyst for boosting the photocatalytic hydrogen evolution reaction performance

Nonmetallic cocatalysts have demonstrated unprecedented potential for accelerating photocatalytic hydrogen evolution reaction (HER). In this study, a nickel phosphide compound, namely Ni5P4, with porous carnation-like superstructure has been target-synthesized and then employed as HER cocatalyst to in-situ build a hybrid with protonated g-C3N4 nanosheets via an electrostatic self-assembly method. Owing to the synergistic advantages of the excellent metallic conductivity and porous carnation-like superstructure of Ni5P4, the as-obtained HCN/Ni5P4 Schottky-junction with abundant active sites, low H* atom adsorption energy and efficient charge carrier transport channel, affords the photocatalytic H-2 production rate of 1157.5 mu mol g(-1) h(-1) when exposed to visible light (lambda > 420 nm). This photocatalytic H-2 production rate was much higher than those of the corresponding reference cocatalysts, namely Ni2P and NiS2 (169.1 and 593.1 mu mol g(-1) h(-1), respectively), both of which were derived from the same Ni(OH)2 precursor. This study provides a new idea for the design of highly active noblemetal-free materials for the photocatalytic HER.