| Photocatalytic technology is an environmentally friendly and sustainable way to overcome environmental and energy problems.It has great development potential in industrial wastewater treatment,especially in the field of dye wastewater decolorization,and the technology has been recognized by the international academic community.Bismuth halide oxide materials have become a current research hotspot in the field of photocatalysis because of their unique light absorption and photocatalytic activity in the UV and visible regions.Although BiOBr and BiOI have the advantages of special crystal structure,electronic structure and indirect band gap jumping,the intrinsic BiOBr and BiOI will suffer from high carrier complexation rate,low visible light utilization and poor catalyst stability in the photocatalytic process,which affect the photocatalytic conversion efficiency,therefore,the modification study of BiOBr and BiOI is needed to enhance their photocatalytic conversion Therefore,there is a need to modify BiOBr and BiOI to improve their photoelectric conversion efficiency.In this thesis,BiOBr and BiOI are investigated to improve their photocatalytic activity through modification and optimization of conditions,which aims to provide some ideas to solve the above two problems.（1）The BiOBr and BiOI photocatalysts were prepared by the solvothermal method to investigate the effect of their preparation conditions on the reaction time of thermal synthesis.The results showed that the BiOBr and BiOI photocatalysts were prepared by the solvent thermal method,and flower-shaped microspherical products with regular appearance and good dispersion were obtained.The results of decolorization experiments on methyl orange under visible light irradiation showed that BiOBr synthesized at 120℃and 14 h and BiOI synthesized at 140℃and 12 h,removed 94.1%and 87.1%,respectively,with good photocatalytic activity.（2）The Al-BiOBr and Al-BiOI photocatalysts were prepared by the solvothermal method,and microspherical products consisting of nanosheets cross-stacked were obtained.The crystalline structures and morphologies as well as the surface compositions and elemental valence states of the catalysts were characterized by XRD,SEM,XPS,and UV-Vis.The results showed that the photocatalytic activities of Al-BiOBr0.3and Al-BiOI0.6composite catalysts were better than those of single composition catalysts and other Al-doped ratio catalysts,and the removal rates of methyl orange could reach 90.6%and 91.9%.（3）The B-BiOBr and B-BiOI sheet photocatalysts were prepared by the solvothermal method,and the products with sheet structure were obtained.The removal of methyl orange by the B-BiOBr0.3and B-BiOI0.3composite doped photocatalysts could reach 98%and 99%under visible light irradiation,showing superior photocatalytic activity than that of single pure phase catalyst and other doped ratio catalyst samples. |
