Defect-engineered WO3−x@Zn3In2S6−x S-scheme heterojunction with atomic interfacial bonds for efficient photothermal-assisted photocatalytic H2O2 production

Photocatalytic production of H 2 O 2 faces challenges such as low charge separation efficiency, narrow light absorption, and sluggish reaction kinetics. This study developed a WO 3− x @Zn 3 In 2 S 6− x S-scheme heterojunction and designed atomic-level W S interface chemical bonds through a defect-induced strategy to address these challenges. Oxygen/sulfur vacancies not only promote the formation of chemical bonds but also trigger a local surface plasmon resonance effect (LSPR) in WO 3− x , enabling full-spectrum light harvesting and photothermal heating. The S-scheme charge transfer retains the high-energy electrons in Zn 3 In 2 S 6− x and holes in WO 3− x to realize dual H 2 O 2 generation pathways. Coupled with LSPR-induced thermal activation, this multidimensional strategy achieved an unprecedented H 2 O 2 yield (3891.2 μmol g −1  h −1 ) under simulated sunlight, which is 9.2 times and 161.5 times higher than that of the non-thermally activated pristine Zn 3 In 2 S 6− x and WO 3− x , respectively. In situ X-ray photoelectron spectroscopy and a series of photoelectrochemical measurements confirmed the S-scheme charge dynamics, and electron spin resonance verified the thermally enhanced reactive oxygen species generation. This work establishes defect-mediated heterointerfacial engineering as a universal paradigm for solar-to-chemical energy conversion and provides feasible insights for designing photothermal-assisted photocatalytic systems.