Enhanced Photocatalytic Performance in Ag+-Induced BiVO4/β-Bi2O3 Heterojunctions.

BiVO₄/β-Bi₂O₃ photocatalysts have been fabricated by a facile Ag doping route. The method involves the substitution of the lattice Bi³⁺ ions in BiVO₄ with dopant Ag⁺ ions, and the supplanted Bi³⁺ ions generate the β-Bi₂O₃ (tetragonal phase) under thermal treatment in air. TEM observations and XRD results confirm that BiVO₄ and β-Bi₂O₃ coexist in the Ag-doped BiVO₄. The diffuse-reflectance spectroscopy (DRS) results demonstrate that all of the BiVO₄/β-Bi₂O₃ photocatalysts show enhanced absorption in the visible region between λ = 550 and 650 nm, and the absorption intensity increases as the Ag content increases. The experimental results reveal that these BiVO₄/β-Bi₂O₃ nanostructures exhibit much higher visible-light photocatalytic activities than that of BiVO₄ for the degradation of the model dye Rhodamine B (RhB) under visible-light irradiation. The enhanced photocatalytic efficiencies are attributed to charge transfer between BiVO₄ and β-Bi₂O₃, which significantly promotes the separation of the photogenerated electrons and holes and, therefore, enhances the photocatalytic properties of the heterojunction. Furthermore, the doped Ag ions might play an important role in this improvement. This approach is expected to be beneficial for the design and optimization of heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]