A novel MoS₂-modified hybrid nanodiamond/g-C₃N₄ photocatalyst for photocatalytic hydrogen evolution

A novel double-heterojunction MoS2/hybrid nanodiamond/g-C3N4 (MoS2/HND/g-C3N4) heterojunction photocatalyst was synthesized by hydrothermal method. The photocatalytic performance of MoS2/HND/g-C3N4 toward H-2 evolution was superior to that of the binary one. In particular, under visible-light irradiation, the MoS2/HND/g-C3N4 nanocomposite photocatalyst with 4 wt% of MoS2 and 3 wt% of HND exhibited the highest photocatalytic hydrogen evolution activity and its corresponding H-2 evolution rate is 227 mu mol g(-1)h(-1), which was about 34 times higher than that of g-C3N4/MoS2-3 %. The origin of the high efficiency can be ascribed to three aspects: (i) graphene shell of HND with high carrier mobility can shorten the charge migration time while the diamond core with light scatter effect can enhance the light absorption efficiency; (ii) the heterostructure formed at the interface of different components can accelerate the charge transfer and separation; (iii) MoS2 quantum dots as cocatalyst can provide active sites, which were needed in the photocatalytic action.