Ultraviolet-visible-near-infrared light responsive inorganic/organic S-scheme heterojunctions for efficient H2O2 production

Abstract

Solar-powered H₂O₂ synthesis from water and oxygen presents a potential strategy in the industrial and environmental domains. However, insufficient light absorption, poor charge separation efficiency, and the same or nearby catalytic sites for the photocatalysts limit the activity of H₂O₂ production. Herein, an ultraviolet-visible-near-infrared light responsive S-scheme heterojunction is created by growing ZnIn₂S₄ (ZIS) subunits firmly on a core of resorcinol-formaldehyde (RF) sphere. The enhanced full-spectrum photon response ZIS/RF core-shell structure is evidenced by UV/Vis-NIR diffuse reflectance spectra (DRS). In situ irradiation X-ray photoelectron spectroscopy (XPS) investigation confirms an S-scheme charge transfer mechanism between RF and ZIS. A directional interfacial electric field (IEF) drives the unique spatial separation feature of constructed heterojunction photoexcited carriers and redox centers through the S-scheme transfer pathway with H₂O₂ production. Under solar light irradiation, the optimized ZIS/RF with core-shell structure shows a robust apparent quantum efficiency (AQY) up to 22.5% at 420 nm, 1% at 720 nm, and 0.2% at 800 nm. With the key reaction intermediates determined by calculating the average number of transferred electrons and oxygen-reactive species, a possible full-spectrum-light-driven redox mechanism of H₂O₂ synthesis is provided.