Preparation And Properties Of BiOX(X=Cl, Br, I) Monomer And Heterojunction Semiconductor Materials

In recent years, BiOX has received much attention due to due to its appropriate band gap andexcellent light utilize efficiency. In the thesis, BiOX (X=Cl, Br, I) monomers and the BiOClBrsosoloids doped by different content of I were synthesized by using a solvothermal method. The crystalstructure and the morphology of the resultant samples were studied by XRD and SEM, and the specificsurface area and pore size distribution structure were studied by using an Nitrogenadsorption-desorption method. Furthermore, the light absorption performance was investigated byUV-Vis spectroscopy and the widths of their band gaps were calculated by further construction ofplotting. In particular, the adsorption performance and photocatalytic capacity research of BiOX (X=Cl, Br, I) monomers and solid solutions were studied.BiOCl and BiOBr showed a good photocatalytic performance. With a catalyst concentration of50mg/200mL, RhB can be degraded completely in100min under the irradiation of full spectrum of Xelamp. BiOI with a similar specific surface area to BiOCl and BiOBr showed an excellent adsorptionperformance to RhB with a saturated adsorption value of197mg/g, which is more than twice of BiOCland BiOBr. By the FT-IR spectroscopy, we confirm it’s not a chemical adsorption progress but aelectrostatic adsorption.Owing to the same crystal structure, it’s very easy for BiOX (X=Cl, Br, I) to form solid solutionsand heterojunction among each other. BiOClBr sosoloid showed a better photocatalytic performancethan BiOCl and BiOBr monomers in RhB photocatalytic degradation experiments. With a catalystconcentration of20mg/200mL,60%RhB can be degraded in2h by BiOClBr under the visible lights,and90%RhB can be degraded in2h by BiOClBr under the visible lights under the irradiation of fullspectrum of Xe lamp. Compared with BiOClBr sosoloid, BiOClBr sosoloid doped by I exhibited abetter adsorption and photocatalytic performance, and95%RhB can be degraded in2h by BiOClBrsosoloid doped by I under the visible lights,95%RhB can be degraded in40min under the irradiationof full spectrum of Xe lamp.In addition, the adsorption performance was determined by the content of I. With the increase ofthe I content, the adsorption of sosoloid to visible lights increased gradually, and the photocatalyticefficiency appeared to be increasing at beginning and decreasing later. The BiOClBr sosoloid with aCl:Br:I ratio of1:1:2showed the best photocatalytic performance, and95%RhB can be degraded in30min under the visible lights,90%RhB can be degraded in20min under the irradiation of fullspectrum of Xe lamp.