Construction of Interfacial P–Ni Bonding for Enhanced Hydrogen Evolution Performance of P-Doped C₃N₄/Ni Photocatalysts

Interface defects are one of the main factors for inefficient photoelectric conversion of nanocomposites, which is also suitable for the photocatalytic nanosystem containing photosensitizers and co-catalysts, so the efficient passivation of interface defects can enhance their photocatalytic performance. In this work, P-doped C3N4 (P–C3N4) was prepared by the thermal polymerization of urea with phytic acid as the P doping source. Then, the doped P atoms could act as anchoring sites for photodeposited Ni nanoparticles (NPs) on P–C3N4, and Ni–P–N bonds were spontaneously formed between Ni NPs and P–C3N4 with doped P as the bridging ligand. The optimal H2 evolution rate of P–C3N4/Ni-20 is 1.56 mmol g–1 h–1, which is 52.0 and 6.0 times that of C3N4 and C3N4/Ni-30, respectively, and even 2.0 times that of P–C3N4/Pt-2%. Its apparent quantum efficiency of 4.35% at 420 nm was 6.9 times that of reference C3N4/Ni-30 without P doping. The optimized interface transfer of carriers by the formed Ni–P–N bonds between P–C3N4 and Ni NPs was the main factor for the enhanced photocatalytic performance of C3N4.