Multivalent Au Nanoparticles Accelerated ZnIn₂S₄ Electron Transfer Kinetics for Sacrificial-Agent-Free of H₂O₂...

Photocatalytic hydrogen peroxide (H₂O₂) production is a promising green and sustainable approach, but achieving high efficiency in pure water systems without the sacrificial agents remains a significant challenge. Here, gold (Au) nanoparticles with varying loadings are photodeposited onto the surface of ZnIn₂S₄ (ZIS) nanoflowers to enhance photocatalytic H₂O₂ production. The optimized Au₁₀₀₀-ZIS sample achieves an exceptional H₂O₂ production rate of 906.13 µmol g^-1 h^-1 under pure water conditions, along with outstanding cycling stability. Mechanistic studies reveal that multivalent Au nanoparticles serve as efficient electron trapping sites, thereby significantly enhancing the spatial separation of photogenerated charge carriers and facilitating rapid charge transfer. This enhanced charge transfer kinetics facilitates H₂O₂ photosynthesis through a dual-channel process (2-electron oxygen reduction and water oxidation) without any additional sacrificial agent. This study enhances the understanding of the critical role of Au as a cocatalyst in photocatalytic processes and presents a promising strategy for sustainable and efficient H₂O₂ production.