Construction of an S-Scheme ZnIn₂S₄/C₃N₄ Heterostructure for Photocatalytic H₂O₂ Generation: Performance Evaluation...

The global demand for hydrogen peroxide (H₂O₂) continues to increase, and photocatalytic H₂O₂ production is regarded as a promising alternative technology due to its mild, safe, and environmentally friendly characteristics. ZnIn₂S₄ has demonstrated promising application potential in photocatalytic H₂O₂ production owing to its unique two-dimensional layered structure and broad spectral response. However, its performance is severely limited by rapid charge recombination and sluggish charge migration. To address this challenge, a ZnIn₂S₄/C₃N₄ S-scheme heterojunction was successfully constructed via a simple oil-bath method by assembling ZnIn₂S₄ nanoflowers on C₃N₄ nanosheets. Systematic structural characterizations and performance evaluations demonstrate that the construction of the S-scheme heterojunction effectively promotes the spatial separation and surface migration of photogenerated charge carriers, thereby significantly enhancing photocatalytic activity. Under optimal conditions, the ZIS/CN-10 sample (C₃N₄ to ZnIn₂S₄ mass ratio of 10%) achieves the highest photocatalytic H₂O₂ production rate of 825.8 μmol g^-1 h^-1. This work provides new insights and theoretical guidance for the rational design of efficient and stable ZnIn₂S₄-based photocatalysts.