Preparation Of Bismuth Ferrites Composites And Photocatalytic Property Under Visible Light

Nowadays,water pollution is one major of the environmental problems,so it is very urgent to solve such problems by various means.In recent years,photocatalytic oxidation technology attracts extensive concerns,which has become a new treatment technology.Although,semiconductor photocatalysts have exhibited excellent performance in the treatment organic pollutant,many problems should be solved,such as low utilization rate of visible light.BiFeO₃ with a narrow band gap is considered promising candidate as semiconductor photocatalyst in the visible range.Therefore,the preparation of BiFeO₃-based composite photocatalysts with high photocatalytic activity has important practical applications.The main contents of this study were summarized as follows:1.Bismuth ferrite（BiFeO₃）nanostructures with various morphologies（spindles,cubes and plates）have been successfully synthesized via a convenient one-pot hydrothermal method.The results show that three kinds of BiFeO₃ products were obtained in this polyvinylpyrrolidone（PVP）-assisted hydrothermal reaction under different alkaline conditions.The resulting nanostructures were characterized using XRD and SEM.Possible formation mechanism for BiFeO₃nanostructures was proposed on the basis of our results.The experiments showed that the visible light absorptive capacity of the Bi FeO₃ nanostructures was significant influenced on the size and morphology.Notably,the as-prepared BiFeO₃ plates with（104）facets exposed exhibit high efficiency for the degradation of methyl orange（MO）under visible light irradiation,suggesting potential applications in photocatalytic and related areas under visible light.2.Graphitic carbon nitride/bismuth ferrite（g-C₃N₄/BiFe O₃）nanocomposites with various g-C₃N₄ contents have been synthesized by a simple method.After the deposition–precipitation process,the novel BiFeO₃ spindle-like nanoparticles with the size of¹00 nm were homogeneously decorated on the surfaces of the C₃N₄ nanosheets.A possible deposition growth mechanism is proposed on the basis of experimental results.The as-prepared g-C₃N₄/BiFeO₃ composites exhibit high efficiency for the degradation of methyl orange（MO）under visible light irradiation,which can be mainly attributed to the synergic effect between g-C₃N₄ and BiFeO₃.The ability to tune surface and interfacial characteristics for the optimization of photophysical properties suggests that the deposition growth process may enable formation of hybrids suitable for a range of photocatalytic applications based on g-C₃N₄.3.Bismuth ferrite/reduced graphene oxide(Bi₂₅FeO₄₀/rGO)nanocomposites have been synthesized by a hydrothermal method,followed by a simple room temperature liquid phase process.Interestingly,X-ray diffraction and scanning electron microscopy analyses indicated that the presence of rGO triggered the transformation of perovskite phase BiFeO₃ to sillenite phase Bi₂₅FeO₄₀0 at room temperature,while the spindle-like morphology was maintained.Under visible light irradiation,the obtained Bi₂₅Fe O₄₀/rGO nanocomposites exhibit high photocatalytic performance for the degradation of methyl orange（MO）,suggesting potential applications in photocatalytic and related areas.Furthermore,the function of rGO for the enhancement of photocatalytic activity and the probable mechanism were also discussed on the basis of the results.