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.　©　2023　Elsevier　B.V.