Enhanced Photocatalytic Performance of NiS₂/g-C₃N₄/SnS₂ by Improving the Charge Diffusion on Both Valence Band and Conduction Band of Carbon Nitride

Herein, a novel Z-scheme heterojunction of nickel disulfide (NiS₂)/graphitic carbon nitride (g-C₃N₄)/(tin disulphide) SnS₂ has been successfully prepared by a simple one-step hydrothermal method. Compared to the pristine g-C₃N₄, a considerable enhancement on the photocatalytic activity of the heterojunction for the photodegradation of methyl orange was obtained, which is attributed to the promoted separation and transfer of the photo-induced exciton due to the formation of Z-scheme mechanism in NiS₂/g-C₃N₄/SnS₂ composites. In particular, the composite of 1 %-NiS₂/g-C₃N₄/SnS₂ shows the highest apparent quasi-first-order rate constant of 0.0633 min⁻¹ for the photodegradation of methyl orange, which is 6.96 times and 2.50 times as large as that of the pristine g-C₃N₄ and 5 %-SnS₂/g-C₃N₄, respectively.