Synergism of sulfur vacancy and Schottky junction in Ni/ZnIn2S4 nanosheet assembly for efficient charge separation and photocatalytic hydrogen evolution

Surface and interface engineering play vital roles on improving the photocatalytic hydrogen evolution. Herein, Ni/ZnIn2S4 nanosheet assembly with sulfur vacancy and Schottky junction (Ni/DZIS) is fabricated through facile ethanediol-assisted solvothermal method. Density functional theory (DFT) calculation reveals that the Ni is absorbed at the hollow site of three S atoms next to sulfur vacancy on the ZnIn2S4 (006) face due to the formation of sulfur vacancy. The resultant Ni/DZIS Schottky junction exhibits high photocatalytic H-2 evolution rate of 703 mu mol g(-1)h(-1) without any noble metal cocatalysts, which is 2.6 times higher than that of pristine ZnIn2S4 nanosheets. The improved photocatalytic performance is mainly attributed to the synergism of sulfur vacancy and Schottky junction accelerating the photogenerated charge transfer and thus inhibiting the charge recombination. Moreover, the photocatalytic performance of Ni/DZIS nearly keeps constant even after six recycles, indicating the high stability and potential applications in field of energy. This work provides a convenient strategy for constructing efficient defective heterojunction assembly photocatalysts via surface and interface engineering.