In-site preparation of H₂O₂ from O₂ and H₂O by way of artificial photosynthesis is highly desirable for facilitating the application of H₂O₂-based advanced oxidation processes (AOPs). It is, however, challenging, due to the severe recombination of the photo-induced charges and the sluggish kinetics of the water oxidation reaction. In this work, a heterojunction of exfoliated K⁺-doped polymeric carbon nitride and the zinc indium sulfide (ZnIn₂S₄) is constructed; an interfacial electric field is induced, and partial charge transfer from ZIS to K-CN is observed via spectroscopic technique. The spatial separation of the photo-induced charges is significantly enhanced, and a remarkable photocatalytic H₂O₂ production from O₂ and H₂O is thus achieved, e.g., 1729.9 μmol h⁻¹ g⁻¹ at the optimum reaction condition with pH value of 9.96 and apparent quantum yield of 2.43 % under the irradiation of 420 nm. Mechanistic investigations indicate the essential role of superoxide radical (O₂^•−) in O₂ to H₂O₂ conversion.

ACS Sustainable Chemistry & Engineering