Interfacial Proton Regulation in an S-Scheme Pt-CQD/K₃PW₁₂O₄₀ Heterojunction Boosts Selective H₂O₂ Synthesis during...

Solar-driven overall water splitting offers a sustainable route for producing hydrogen and hydrogen peroxide, yet achieving high H₂O₂ selectivity remains challenging due to competing proton-coupled electron transfer pathways. Here we construct an S-scheme heterojunction composed of carbon quantum dots (CQDs) and K₃PW₁₂O₄₀, where the built-in electric field at the interface enhances charge separation and promotes proton transfer, creating a favorable microenvironment for selective H₂O₂ generation. This catalyst achieves H₂ and H₂O₂ production rates of 603 and 586 μmol/g·h simultaneously under visible light irradiation. The tailored electronic structure lowers energy barriers for key intermediates, facilitating selective H₂O₂ production. These findings demonstrate that interfacial proton regulation combined with broad light absorption and efficient charge separation can guide the design of multifunctional photocatalysts for scalable solar-driven H₂O₂ synthesis.