Novel recyclable BiOBr/Fe3O4/RGO composites with remarkable visible-light photocatalytic activity

Magnetic BiOBr/Fe3O4/RGO composites with remarkable photocatalytic capability were prepared by a simple hydrothermal method to load 3D flower-like microspherical BiOBr onto the surface of Fe3O4/RGO. Under visible-light irradiation (lambda > 420 nm), the BiOBr/Fe3O4/RGO composite with 56% mass percentage of Fe3O4/RGO shows the optimal removal ability for Rhodamine B, and the total removal efficiency is 96%. The coupling of Fe3O4/RGO and BiOBr elevates the conduction band of BiOBr, which enhances the reduction level of BiOBr/Fe3O4/RGO composites. Ultimately, based on experiments and theoretical calculations, an n-type Schottky contact formed at the heterojunction interface between RGO doped with Fe3O4 and BiOBr is proposed for photoexcited charge transfer. The RGO with great adsorptivity plays a major role in the photocatalysts composed of BiOBr, RGO and Fe3O4. Further, BiOBr/Fe3O4/RGO composites with permanent-magnetism can be recovered and reused easily by external magnetic field and maintain a total removal efficiency of 90% after four cycles.