Study On Preparation And Photocatalytic Properties Of Modified Bismuth Vanadate

Bismuth vanadate is a relatively narrow band width(2.3 ~2.4 e V)and is close to the center of the solar spectrum(2.6 e V),which is an ideal photocatalytic material for visible light response.However,bismuth vanadate also has some defects: 1.Bismuth vanadate catalyst has a higher composite probability of photoelectric and void.2.The degradation rate of light is slower;3.Bismuth vanadate catalyst has low utilization rate of visible light.For the above problems,the following research is carried out in this paper:(1)The pure Bi VO4 catalyst CQDs/Bi VO4 composite catalyst was successfully prepared by sol-gel method and hydrothermal method respectively.Best Bi VO4 catalyst calcination temperature is 500 ?.Best CQDs/Bi VO4 catalyst preparation conditions: calcination temperature is 150?,carbon bismuth ratio 1.5,the reaction time of 12 h.Cu-Bi VO4 catalyst prepared by impregnation method,Cu-Bi VO4 best catalyst calcination temperature is 350?.The hydrothermal CQDs/Cu-Bi VO4 best compound catalyst preparation conditions for the calcination temperature is 120?,carbon bismuth ratio 1.5,the reaction time of 12 h.(2)The structure of the catalyst was characterized by XRD,SEM and UV-vis diffuse reflectance,and the photocatalytic activity of the catalyst was tested by using the halogen lamp to simulate the sunlight.The results show that carbon doping can effectively increase the photocatalytic activity of bismuth vanadate,shift the absorption band of bismuth vanadate to sunlight,and narrow the band gap of bismuth ferrite.,The CQDs/Bi VO4 composite catalyst prepared under the best preparation conditions has a band gap of about 1.98 e V.(3)The degradation of methyl orange solution as the target degradation of photocatalytic experiments to explore CQDs/Bi VO4 catalyst processing methyl orange solution of the main factors and the best reaction conditions.The main influencing factors are the initial p H value of methyl orange solution,the dosage of catalyst and the initial concentration of solution.The optimal reaction conditions of methyl orange solution catalyzed by CQDs/Bi VO4 composite catalyst were as follows: the initial p H value of methyl orange solution was 7,the dosage of catalyst was 2.5 g / L and the initial concentration of methyl orange solution was 10 mg/L.Under optimum reaction conditions,the methyl orange solution was treated with CQDs/Bi VO4 catalyst prepared under the optimal conditions for 75 minutes under photocatalytic conditions.The color removal rate of methyl orange solution was 98.16%.(4)The photocatalytic degradation experiments with methylene blue solution as the target degradant were carried out to investigate the main influencing factors and the optimum reaction conditions for the treatment of methylene blue solution with CQDs/Cu-Bi VO4 catalyst.The main influencing factors are the initial p H value of methylene blue solution,the dosage of catalyst and the initial concentration of solution.The optimum reaction conditions for the catalytic methylene blue solution of CQDs/Cu-Bi VO4 composite catalyst were as follows: the initial p H value of methylene blue solution was 7,the dosage of catalyst was 2.5 g/L and the initial concentration of methylene blue solution was 10 mg/L.Under optimum reaction conditions,the photocatalytic activity of methylene blue solution treated with CQDs/Cu-Bi VO4 catalyst prepared under optimal conditions for 75 minutes,the methylene blue solution has a colorimetric removal rate of 99.56%.