N, O-Doped surface modulation of ZnIn2S4 with high hydrophilicity for enhanced photocatalytic hydrogen evolution

Heteroatom doping is a promising strategy for optimizing the photocatalytic activity of semiconductors. However, relying solely on single-element doping often poses challenges in modulating the capabilities of semiconductors. Herein, we adopt a strategy of simultaneously modifying ZnIn 2 S 4 with the double non-metallic elements nitrogen (N) and oxygen (O) to form (N, O)-ZnIn 2 S 4 . Interestingly, (N, O)-ZnIn 2 S 4 exhibits significantly higher hydrophilicity and specific surface area compared to pristine ZnIn 2 S 4 . The contact angle decreases from 24° to 21°, while the specific surface area increases from 56 m 2 /g to 75 m 2 /g. The hydrogen production rate of (N, O)-ZnIn 2 S 4 reaches 400 μmol/h/g, which is 2.52 times higher than that of pristine ZnIn 2 S 4 . Photoelectrochemical characterization reveals that (N, O)-ZnIn 2 S 4 has a lower overpotential, higher photocurrent, lower resistance, reduced fluorescence intensity, and shorter fluorescence lifetime. Additionally, co-catalyst loading boosts the hydrogen production activity of ZnCo 2 S 4 /(N, O)-ZnIn 2 S 4 from 548 μmol/h/g to 810 μmol/h/g, compared to ZnCo 2 S 4 /ZnIn 2 S 4 . This study presents a dual non-metallic modification strategy to enhance semiconductor properties, achieving superior performance in photocatalytic hydrogen production.