Study On The Modification Of Bismuth Oxyhalide And Its Photocatalytic Properties

BiOX is a new photocatalyst with unique lamellar structure,which has been widely studied in recent years.However,pure phase BiOX still has some limitations.In order to further improve the performance of BiOX,this study modified BiOX with cationic and anion doping,and studied its effect on photocatalytic performance.The specific contents are as follows:?1?Anion doping:two series of catalysts,BiOBr _XCl_1-X and BiOBrXI_1-X,were prepared by solvent heating with halogen anions doped with each other.The characterization of the catalyst system and the catalytic degradation performance under visible light were tested by means of SEM,XRD,UV-Vis and photochemical test.The results show that in the BiOBrXCl_1-Xseries,with the increase of Br content,the material maintains a 1?m size microsphere structure composed of nanosheets.The visible light degradation experiment results showed that BiOBr_0.2Cl_0.8 had better photocatalytic performance,low impedance and high charge transfer rate were the direct reasons for its high performance.In BiOBr _XI_1-X-X series,the morphology of BiOBr_0.6I_0.4 shows a smaller chestnut bract structure and a much higher specific surface area than that of pure BiOI and BiOBr.It was found that BiOBr_0.6I_0.4 had the best photocatalytic activity.The degradation rate of rhodamine B?RhB?was more than 95%in 15 minutes.Photochemical testing and fluorescence spectroscopy have also proved that BiOBr_0.6I_0.4has higher charge transfer rate and is not easy to compound photogenic carriers,which provides a favorable evidence for the excellent photocatalytic performance of BiOBr_0.6I_0.4.?2?Aationic doping:Bi_1-XGa_XOI and Bi_1-XIn_XOI series samples were prepared by doping BiOI with the third periodic element Ga and the fourth periodic element In whose atomic radius is smaller than Bi.The experimental results showed that with the increase of Ga doping ratio,the microsphere structure of BiOI material was obviously destroyed,and the XRD test showed that the solid solution structure was generated,and the photocatalytic activity decreased.However,In the study of Bi_1-XIn_XOI,it was found that the morphology of BiOI was not significantly changed with a small amount of doping of In ions,and the original nanoparticle particle shape was still maintained.Photochemical test showed that Bi_0.98In_0.02OI had the highest photogenerated current density,and it also showed high photocatalytic performance In the photocatalytic degradation of RhB experiment.The appropriate doping of In could effectively improve the photocatalytic activity of BiOI.