Built-in electric field mediated S-scheme charge migration in COF/In2S3 heterojunction for boosting H2O2 photosynthesis and sterilization

The construction of step-scheme (S-scheme) heterojunctions has emerged as a widely adopted strategy for achieving photocatalytic hydrogen peroxide (H2O2) generation. In this study, we employed an approach to deposit indium sulfide (In2S3) onto a Schiff-base covalent organic framework (COF), namely TpMA, for H2O2 photosynthesis and its sterilization application. The optimized photocatalyst, 10%TpMA/In2S3, exhibited remarkable photocatalytic performance, yielding a substantial H2O2 output of 311.07 μmol/L. A series of advanced instrumental analyses and density functional theory (DFT) results indicated that the establishment of the S-scheme heterojunction played a pivotal role in facilitating efficient charge carrier transfer and separation. Specifically, the formation of a built-in electric field was probed and quantified. Furthermore, the H2O2 exhibited the capability to undergo direct catalysis by Fe(II), which substantially facilitated the inactivation of pathogenic bacteria. This work unveils insight into the COF-based S-scheme photocatalysts and offers a sustainable approach for environmentally friendly H2O2 production for sterilization purposes.