Preparation And Structural Properties Of BiOCl/SrFe_12-xCO_xO₁₉/rGO

BiOCl is a typical UV photocatalyst,which with a unique layered structure and the[Bi₂O₂]²⁺layer is sandwiched by two[Cl₂]^2-layers.The vertical direction of[Bi₂O₂]²⁺and[Cl₂]^2-layers are likely to cause the separation of photogenerated electron-hole pairs,so it has good photocatalytic activity.However,the absorption of visible light is limited due to its large band gap?about 3.46 eV?.In addition,the recycle of BiOCl is also a problem in reaction system.Based on this,SrFe₁₂O₁₉ magnetic matrix was prepared by hydrothermal method,modified with Co to prepare SrFe_12-xCo_xO₁₉ with more stable magnetic properties,and then further synthesized the magnetic composite photocatalysis BiOCl/SrFe_12-xCo_xO₁₉.A BiOCl/SrFe_12-xCo_xO₁₉/rGO material with high photocatalytic activity was prepared by compositig BiOCl/SrFe_12-xCo_xO₁₉ with rGO.The SrFe₁₂O₁₉ and SrFe_12-xCo_xO₁₉ substrates have been prepared by hydrothermal method,and then BiOCl/SrFe₁₂O₁₉ and BiOCl/SrFe_12-xCo_xO₁₉ have prepared by hydrothermal method again.The samples have characterized by XRD,FTIR,XPS,SEM,TEM,SEAD,EDS,Uv-vis and VSM,etc,and the catalytic activity was determined using RhB as the target dye.SrFe₁₂O₁₉ and SrFe_12-xCo_xO₁₉ can promote the growth of?001?and?110?on BiOCl crystal planes.The specific surface area and pore size of BiOCl/SrFe_12-xCo_xO₁₉ are larger than those of BiOCl/SrFe₁₂O₁₉,and Co in BiOCl/SrF_e12-xCo_xO₁₉ is in the form of Co²⁺and Co-O.Uv-vis shows that the combination of magnetic matrix and BiOCl can reduce the band gap.VSM shows that the coercivity and Mr/Ms of BiOCl/SrFe_12-xCo_xO₁₉ are large,which is more conducive to environmental recycling and reuse.The photocatalytic activity shows that the degradation rates of RhB in BiOCl/SrFe₁₂O₁₉ and BiOCl/SrFe_12-xCo_xO₁₉ are 96.3%and98.2%,and those after four cycles are 70.0%and 61.8%,respectively.GO was prepared by the modified Hummers method.Then BiOCl/rGO,BiOCl/SrFe₁₂O₁₉/rGO and BiOCl/SrFe_12-xCo_xO₁₉/rGO have been prepared by hydrothermal method.The optized samples have characterized by XRD,FTIR,SEM,TEM,SEAD,EDS,Uv-vis and VSM.RhB as the target dye to determine the catalytic activity of the composite catalysts.The degradation rate of RhB shows that the degradation rates of?0.5%?BiOCl/SrFe₁₂O₁₉/rGO and?1%?BiOCl/SrFe_12-xCo_xO₁₉/rGO at 80 min were respectively 95.9%and 94.2%.And the catalysis after four repeated degradations,the activity is over than 80%,indicating that the photocatalytic activity of the composite magnetic photocatalyst composited with graphene was strengthened..VSM shows that?1%?BiOCl/SrFe_12-xCo_xO₁₉/rGO has higher Mr/Ms value and coercivity?Hci?,which is more favorable for recycling.The magnetic matrix has excellent stability because the incorporation of the Co²⁺enhances the anisotropy and coercive force of the magnetic matrix,and a magnetic composite photocatalyst with excellent magnetic properties was obtained by the matrix composited with the catalytic active matter.The reason on activity enhancement of the composite magnetic photocatalytic is as follows.The combination of BiOCl and a magnetic matrix enhances the photosensitizing process of BiOCl,which enhances the absorption and utilization of visible light,and makes up for the low absorption of visible light by BiOCl.In graphene composite magnetic photocatalytic materials,rGO distributed on the surface of BiOCl,which accelerates the separation of electron-hole pairs,and quickly transfers electrons and holes to the surface of the magnetic catalyst,enhancing the overall photocatalytic activity.