Hydrothermal preparation and visible light photocatalytic activity of Bi25FeO40-graphene nanocomposite

A visible light active Bi₂₅FeO₄₀-graphene photocatalyst was prepared by a facile one-step hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and BET surface area measurements. The XRD characterizations indicated that the bismuth ferrite-graphene nanocomposite was Bi₂₅FeO₄₀-graphene, while the pure bismuth ferrite without graphene was BiFeO₃. In comparison with the pure BiFeO₃ catalyst, the Bi₂₅FeO₄₀-graphene existed better magnetism, smaller particle size and larger specific surface areas, which indicated that the addition of graphene have an effect on the dispersion of bismuth ferrite and the crystallization process during hydrothermal preparation of catalyst. The resulting BiFeO₃ and Bi₂₅FeO₄₀-graphene photocatalysts were used to visible light photocatalytic degradation of methylene blue (MB) in water under visiblelight irradiation (λ > 420 nm). It was found that the Bi₂₅FeO₄₀-graphene nanocomposite exhibits significantly higher photocatalytic activity than the pure BiFeO₃ due to the synergism effect of Bi₂₅FeO₄₀ and graphene. In addition, Bi₂₅FeO₄₀-graphene nanocomposite particles have a strong magnetic property, which can be recovered by magnetic separation, and therefore be reused easily.