Heterointerface Engineering of In ₂ S ₃ /Ag ₂ S S‐Scheme Photocatalyst Toward Solar Hydrogen Peroxide Photosynthesis

Photocatalytic hydrogen peroxide (H₂O₂) production offers a sustainable alternative to the energy-intensive anthraquinone process. However, developing efficient semiconductor systems for oxygen reduction to H₂O₂ remains challenging. Herein, we construct an In₂S₃/Ag₂S heterostructure via a cation-exchange strategy, achieving atomic-level interfacial modulation that enhances charge separation and boosts H₂O₂ production. Spectroscopic and radical trapping experiments identify the dominant active species and confirm a favorable two-electron oxygen reduction pathway. The tailored energy band alignment between In₂S₃ and Ag₂S promotes visible-light absorption and facilitates efficient carrier migration, leading to significantly improved photocatalytic performance. This work provides a feasible approach to designing transition metal chalcogenides (TMCs)-based heterostructures for sustainable H₂O₂ synthesis and advances solar-to-chemical energy conversion.