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 (λ > 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.