Novel CoS/ZnIn2S4 S-scheme heterojunction for efficient visible-light photocatalytic H2O2 production via dual-channel reactions in air
Photocatalytic production of hydrogen peroxide (H2O2) using water and O2 offers an economical, environmentally friendly, and sustainable route for H2O2 synthesis. However, current photocatalytic systems suffer from poor charge carrier transport, narrow light absorption, and insufficient active sites, leading to unsatisfactory H2O2 production efficiency. In this study, a CoS/ZnIn2S4 (ZIS) composite was constructed by in-situ growing CoS nanoclusters on ZIS via a solvothermal method for photocatalytic H2O2 production. The integration of CoS with ZIS broadened the light absorption spectrum. The optimized CoS/ZIS-3 composite exhibited an exceptional H2O2 production rate of 2693.39 μmol g−1 h−1 under visible light in isopropanol, surpassing pristine ZIS and CoS by factors of 6.54 and 18.08, respectively. The S-scheme heterojunction and built-in electric field synergistically enhanced the separation and transportation of photogenerated charge carriers, thereby improving photocatalytic efficiency. The H2O2 synthesis mechanism involves dual-channel oxygen reduction and water oxidation reactions mediated by CoS/ZIS. The produced H2O2 effectively degraded organic pollutants and inhibited the growth of E. coli. This study presents a promising green strategy for enhancing ZIS-based photocatalysts through constructing S-scheme heterojunctions for efficient H2O2 synthesis.