Studies On Synthesis And Properties Of Bi₂S₃/BiOBr Composite Magnetic Visible Light Catalyst

BiOBr has a great research prospect in photocatalytic treatment of organic wastewater,however,the BiOBr holds low utilization efficiency of sunlight and the photogenic electron and hole are difficult to separate effectively.So it is necessary to modify the high recombination rate of BiOBr for improving the performance.In this study,the photocatalytic activity of BiOBr was improved by controlling the morphology,compositing of narrow band gap semiconductor and loading of magnetic materials.The self-assembly of BiOBr nanosheets with disordering arrangement was carried out by adding surfactant?PEG?by hydrothermal method.The self-assembly BiOBr?Z-BiOBr?and disordered BiOBr?W-BiOBr?were consist with tetragonal BiOBr.The band gap of Z-BiOBr was smaller than that of W-BiOBr by UV-vis DRS.By comparing the photocatalytic degradation of RhB dye wastewater with Z-BiOBr and W-BiOBr catalysts,it was found that the photocatalytic activity of Z-BiOBr was high,and the degradation efficiency of RhB reach 90.1%after 20 min with the so-prepared photocatalyst under visible light illumination.Bi₂S₃/BiOBr was prepared by the mixed solvent thermal method with ethylene glycol and water.The product was characterized by XRD,XEM,BET,PL and UV-vis DRS.XRD test showed that Bi₂S₃ and BiOBr were orthorhombic and tetragonal crystal type respectively.Bi₂S₃ did not change the crystal type of BiOBr,and the diffraction peaks corresponding to the crystal surfaces of Bi₂S₃?021?and?230?were exposed.The so-prepared sample was observed to be a micron ball stacked on nanometer sheet by SEM characterization.The band gap width of the composite was narrowed.BET was used to determine the specific surface area of BiOBr and composite 10%Bi₂S₃/BiOBr,which were 43.3m²/g and 45.5m²/g respectively.By taking RhB,a simulated dye,as the degradation pollutant,and combining with 10%Bi₂S₃/BiOBr,the catalyst had the best effect.After 8 min of light,the degradation efficiency of RhB reached 93%.The capture experiment of active groups,it was found that.O₂^-was the most important.PL spectral revealed,the separation efficiency of photogenerated electrons and holes was improved after compound Bi₂S₃.The results of LSV and EIS show that 10%Bi₂S₃/BiOBr has better electrochemical performance.Bi₂S₃/BiOBr/SrFe₁₂O₁₉ composite photocatalyst was produced in this work.By the structure of characterization,the product was Bi₂S₃/BiOBr/SrFe₁₂O₁₉.The hysteresis loop of SrFe₁₂O₁₉ and Bi₂S₃/BiOBr/SrFe₁₂O₁₉ was tested by VSM,proving with high magnetization performance.With RhB as the simulated dye wastewater,when the amount of SrFe₁₂O₁₉ was 5%,the photodegradation efficiency of the catalyst was the highest at 91.6%.Taking landfill leachate as the actual sewage,it was showed that the magnetization in the compsite had certain capacity of removing pollutant in landfill leachate through the spectrum of sewage and the change of sewage color after photocatalytic degradation,but failing to reduce the COD of sewage.And this work needs to be practiced in the furture study.