S vacancies engineering ZnIn2S4 nanosheets for boosted photocatalytic hydrogen evolution

Abstract

2D-layered ZnIn2S4 nanosheets (ZIS NSs) have been considered as a promising photocatalysts to produce H2. Nevertheless, the carrier recombination of 2D ZnIn2S4 is still severe, which limits its photocatalytic efficiency and practical applications. Herein, the defective ZnIn2S4 nanosheets with S vacancies (DZIS NSs) is fabricated via an easy one-step solvothermal process only by changing the used solvent without a complex physical or/and chemical secondary treatment, which can realize efficient photocatalytic H2 generation. The resultant DZIS NSs show enhanced photocatalytic hydrogen evolution reaction (HER) activity and well stability after 5 cycles. And the photocatalytic HER rate of DZIS NSs is up to 5437 μmol−1 h−1 g−1, nearly 2.6 times of pristine ZIS NSs (2090 μmol−1 h−1 g−1). The experimental data suggest that the excellent photocatalytic HER performance of DZIS NSs is attributable to the existence of S vacancies, which can form a S defect energy level under the lower conduction band (CB), offering abundant active sites for hydrogen activation, extending the visible light absorption range and narrowing the bandgap of DZIS NSs. Such defect engineering strategy opens new avenues for other sulfide photocatalysts to further boost photocatalytic activity.