Controllable in situ synthesis of BiOBrxI1−x solid solution on reduced graphene oxide with enhanced visible light photocatalytic performance

Abstract

Novel composite photocatalysts, BiOBr_xI_1−x–rGO, were facilely prepared by in situ controllable deposition of BiOBr_xI_1−x solid solutions onto the surface of graphene oxide which was then reduced at mild conditions. The high-resolution transmission electron microscopy results revealed an intimate interface between BiOBr_xI_1−x and rGO in the composites. The UV-vis diffuse reflectance spectra showed that BiOBr_xI_1−x–rGO composites had intense optical absorption in the visible light region. These excellent structural and spectral properties endowed BiOBr_xI_1−x–rGO composites with enhanced photocatalytic performance. Significantly, the BiOBr_0.6I_0.4–rGO sample exhibited the best photocatalytic activity for the photodegradation of methyl orange under visible light irradiation (λ > 420 nm). The enhanced photocatalytic activity could be attributed to more effective charge separation and transportation, and increased light absorption. The radical trapping experiments confirmed that holes and superoxide radical species were the two main reactive species in the photocatalysis process. Moreover, this material exhibited great stability and durability, which retained more than 80% degradation after several cycles.