Suppression of hydrogen-related defect in ZnWO 4 /HRP S-scheme heterojunction to enhance internal charge transfer in materials

In photocatalytic degradation of pollutants, hydrogen-related defects on the catalyst surface inhibit the generation of highly reactive hydroxyl radicals (·OH) and superoxide radicals (·O ₂ ⁻ ). Therefore, strategies to mitigate such defects are crucial for enhancing photocatalytic efficiency. To address this challenge, ZnWO ₄ /HRP heterojunction photocatalysts were successfully prepared via a simple hydrothermal method, constructing a compact interfacial structure where rod-shaped ZnWO ₄ uniformly attaches to the HRP surface. Photocatalytic performance tests revealed that the composites exhibited excellent catalytic activity for rhodamine B (RhB) degradation, with a rate constant of 0.21 min ^− 1 within 15 min − 3.5 and 21 times higher than those of individual HRP and ZnWO ₄ , respectively. Moreover, due to the robust chemical structure and strong interfacial bonding between ZnWO ₄ and HRP, the composite maintains high photocatalytic stability across multiple catalytic cycles. Mechanistic analysis demonstrates that the S-scheme heterojunction effectively suppresses the formation of hydrogen-related defects on the ZnWO ₄ surface, significantly reducing surface defect state density. This inhibition enhances photogenerated carrier separation, accelerates charge transfer, and facilitates the efficient generation of ·O ₂ ⁻ . By adopting a heterojunction strategy to address hydrogen - related defects, the catalyst’s visible-light absorption capacity, photoelectric conversion efficiency, and radical generation efficiency were enhanced, while carrier recombination was suppressed. These findings provide new insights for designing high-efficiency heterojunction photocatalysts and highlight their promising potential in photocatalytic removal of organic pollutants.