Enhanced bifunctional visible-light-driven photocatalytic production of H2 and H2O2 enabled by Ag-ZnIn2S4/C-In2O3 S-scheme heterojunction

We reported the preparation of Ag-ZnIn2S4/C-In2O3 S-scheme heterojunction for boosting bifunctional photocatalytic hydrogen and hydrogen peroxide production activity. [Display omitted] •A novel Ag incorporating ZnIn2S4/C-In2O3 S-scheme heterojunction photocatalysts was synthesized.•The boosted bifunctional photocatalytic production of H2 evolution and H2O2 was achieved.•The mechanism of the enhanced photocatalytic performance was deeply investigated.•The dual modulation of heterojunctions and defect were clarified as an effective strategy for multifunctional photocatalyst. Multifunctional photocatalysts are recognized as efficient solutions to complex energy and environmental challenges. In this study, we report the rationally-designed bifunctional photocatalysts of Ag-ZnIn2S4/C-In2O3 (AgZISCIO) with S-scheme heterojunction and defect engineering, for highly efficient production of both hydrogen and hydrogen peroxide production. The heterojunction is established by growing ZnIn2S4 (ZIS) nanosheets on MOF-derived C-doped In2O3 (CIO) nanorods, which favors the formation of built-in electric field, thus facilitating effective photogenerated charge separation. Moreover, by introducing Ag ions into ZIS lattice via a cation exchange reaction, abundant active sites would be created for inducing defects on the heterojunction surface, thereby enhancing the kinetics of oxidation–reduction processes. Under visible-light irradiation, the resultant AgZISCIO photocatalysts exhibit remarkable hydrogen and hydrogen peroxide production rates of 3.19 mmol·g−1·h−1 and 2.42 mmol·g−1·h−1, respectively, outperforming those of most In2O3-based photocatalysts reported recently. It is witnessed that the overall enhanced photocatalytic performance could be mainly attributed to the formed S-scheme heterojunction and defect creation for improved photogenerated charge separation and redox capabilities. This work underscores the importance of dual modulation of heterojunctions and defect engineering as an effective strategy for enhancing photocatalytic performance, providing some valuable insights for developing advanced multifunctional photocatalysts.