Construction of a BiOCl/Bi2O2CO3 S-Scheme Heterojunction Photocatalyst via Sharing [Bi2O2]2+ Slabs with Enhanced Photocatalytic H2O2 Production Performance

The construction of a close contact interface is key to enhancing the photocatalytic activity in heterojunctions. In the work, the BiOCl/Bi₂O₂CO₃ of sharing [Bi₂O₂]²⁺ slabs S-scheme heterojunction was prepared by a HCl in situ etching method. The optimal composite photocatalyst could accomplish sizable productivity of H₂O₂ to 2562.95 μmol g^-1 h^-1 under simulated solar irradiation, higher than that of primitive Bi₂O₂CO₃ and BiOCl. Moreover, the synthesized catalysts showed good stability. The band structures of BiOCl and Bi₂O₂CO₃ were determined, confirming the formation of BiOCl/Bi₂O₂CO₃ S-scheme heterojunction The BiOCl/Bi₂O₂CO₃, which obviously improved the separation efficiency of photoinduced carriers and effectively enhanced the redox ability of the photocatalyst. In addition, density functional theory (DFT) calculations were utilized to analyze the electron transfer properties and the constitution of the built-in electric field at the interface of BiOCl and Bi₂O₂CO₃. The photocatalytic reaction process was further researched by electron paramagnetic resonance (EPR), indicating the active species in the photocatalytic production of hydrogen peroxide. Eventually, a feasible S-scheme electron transfer mechanism on the BiOCl/Bi₂O₂CO₃ heterojunction during the photocatalytic H₂O₂ production process was proposed and discussed. This work provides a reliable strategy for the fine design of the S-scheme heterojunction.