Internal electric field steering S-scheme charge transfer in ZnIn2S4/COF boosts H2O2 photosynthesis from water and air for sustainable disinfection

Abstract The global need for clean water and sanitation drives the development of eco-friendly and efficient water treatment technologies to combat biological pollution from pathogens. In this study, a novel heterojunction photocatalyst was synthesized by incorporating ZnIn 2 S 4 into covalent organic frameworks (COFs) to enable environmentally friendly hydrogen peroxide (H 2 O 2 ) photosynthesis and explore its potential for in situ disinfection. The ZnIn 2 S 4 /COF photocatalyst achieved remarkable H 2 O 2 yields of 1325 µmol∙g − ¹∙h − ¹, surpassing pristine COF and ZnIn 2 S 4 by factors of 3.12 and 16.2, respectively. The produced H 2 O 2 was efficiently activated into hydroxyl radicals (·OH) through reaction with Fe(II), enabling rapid sterilization via a photocatalysis-self-Fenton system. Mechanistic insights, supported by physicochemical characterizations and theoretical calculations, highlighted the role of the internal electric field (IEF) in enhancing carrier separation and transfer, thereby boosting photosynthesis efficiency. This work presents a sustainable approach to H 2 O 2 photosynthesis and activation for disinfection, offering a promising solution to global water treatment challenges.