Enhanced visible-light-driven photocatalytic hydrogen generation over g-C₃N₄ through loading the noble metal-free NiS ₂ cocatalyst

Nickel sulfide nanoparticles were successfully grown as a cocatalyst on the surface of polymeric g-C₃N₄ photocatalysts through a hydrothermal method. The NiS₂ composition is confirmed by various spectroscopic techniques and electron microscopy. It was found that the presence of NiS₂ nanoparticles on the g-C₃N₄ surface could greatly enhance the photocatalytic activity of g-C₃N ₄ for hydrogen generation under visible-light irradiation. Significantly, the NiS₂-loaded g-C₃N₄ was capable of showing an even higher photocatalytic H₂ generation rate than that of Pt-loaded g-C₃N₄. Such enhanced photocatalytic activities by NiS₂-loading could be attributed to the effective charge transfer between g-C₃N₄ and the attached NiS₂ nanoparticles which might also serve as active sites for proton reduction into H₂. Our studies demonstrate a promising strategy to develop economic noble-metal-free composites as photocatalysts for efficient solar-to-hydrogen conversion.