Noble metal-free NiS2 with rich active sites loaded g-C3N4 for highly efficient photocatalytic H2 evolution under visible light irradiation.

A series of noble-metal-free NiS2-loaded g-C3N4 hybrid composites were prepared via simple hydrothermal method. Benefited from the wider spectral response range and the effective separation of photoelectron-holes of g-C3N4-NiS2 heterojunction catalysts, as well as the rich unsaturated active S atoms on the NiS2 with S22-, the composite catalysts has prominent photocatalytic performance for H2 evolution. Remarkably, the optimal composite photocatalysts achieved an average hydrogen production rate as high as 715.83 μmol/h/g in 3 h under visible-light irradiation, which is 2.75 times as high as that of precious metal Pt (259.5 μmol/h/g) as a co-catalyst. Besides, the composite catalyst still shows prominent photocatalytic performance for H2 evolution after three continuous photocatalytic reaction cycles for 9 h. This study provided a facile method to build a low-cost but effective metal sulfide co-catalyst for hydrogen production under visible light irradiation.