Construction of a Z-scheme heterojunction bifunctional photocatalyst with Ag-modified AgBr embedded in β-Bi2O3 flowers

Abstract

β-Bi₂O₃ demonstrates excellent photocatalytic activity under visible light, but it has a very high photogenerated e⁻–h⁺ recombination rate and quite low quantum efficiency. AgBr also shows excellent catalytic activity but Ag⁺ is easily reduced to Ag under light radiation, which limits its application in the photocatalysis field, and there are few reports about the application of AgBr in photocatalysis. In this study, the spherical flower-like porous β-Bi₂O₃ matrix was first obtained, and then the spherical-like AgBr was embedded between the petals of the flower-like structure to avoid direct light radiation. The only light through the pores on the β-Bi₂O₃ petals could be transmitted onto the surfaces of AgBr particles to form a nanometer point light source, which photo-reduced Ag⁺ on the surface of the AgBr nanospheres to construct the Ag-modified AgBr/β-Bi₂O₃ embedded composite and a typical Z-scheme heterojunction was constructed. Under this bifunctional photocatalyst and visible light, the RhB degradation rate reached 99.85% in 30 min, and the photolysis water hydrogen production rate reached 6.288 mmol g⁻¹ h⁻¹. This work is as an effective method for not only the preparation of the embedded structure, quantum dot modification and flower-like morphology but also for the construction of Z-scheme heterostructures.