Novel flower-like SnIn4S8/WO3 S-scheme heterojunction photocatalysts for enhanced oxidation of 5-hydroxymethylfurfural

Solar biomass conversion has garnered significant research attention, but the rapid recombination of electrons and holes in photocatalysts hinders efficiency. To enhance this process, researchers aim to develop S-scheme heterojunction photocatalysts with optimized band structures that enable effective electron-hole separation, thereby improving overall efficiency. Herein, chemical-bonded SnIn4S8/WO3 S-scheme heterostructure photocatalyst was constructed via in-situ hydrothermal strategy for sunlight-driven catalytic selective oxidization of 5-hydroxymethylfurfural (HMF) into valuable 2,5-dimethylfuran (DFF). X-ray photoelectron spectroscopy (XPS) results prove the formation of a W–S chemical bond in the composites, which will likely enhance the efficient transport of photogenerated charges. The optimal SnIn4S8/WO3 exhibited an excellent HMF conversion rate (89%) and DFF yield (68%) after 2 h. The S-scheme charge transfer pathway in the SnIn4S8/WO3 composite structure was verified through density functional theory (DFT) calculations and supported by partial in situ experimental results. This study demonstrates that the S-scheme heterostructure based on SnIn4S8 offers innovative insights for advancing photocatalytic biomass conversion.