Research On Syntheses And Activities Of Visible-Light-Driven Photocatalysts Of BiVO₄ And Bi₂MoO₆ Composites

With the continuous development of society,the current energy crisis and environmental pollution problems are increasingly serious,the use of solar photocatalytic degradation of organic pollutants has become an important mean to solve this problem.BiV04 and Bi2MoO6 are two typical bismuth photocatalytic materials with good absorption of visible light,but their low activity limits their practical application.In this paper,the design and synthesis of composite semiconductor materials based on BiV04 and Bi2MoO6 were explored.The activity and mechanism of Bi2Mo06/BiVO4,AgVO3/BiVO4 and FeV04/Bi2MoO6 composite photocatalysts were investigated.The main contents of this paper are as follows:1.Bi2MoO6 and BiVO4 were prepared by hydrothermal method,then Bi2MoO6/BiVO4 composite photocatalyst was prepared by impregnation-heat treatment.The crystal phase composition,surface morphology,elemental composition and valence and light absorption properties of Bi2MoO6/BiVO4 composite photocatalyst were analyzed by XRD,SEM,EDS,XPS and UV-vis.The effect of Bi2MoO6 composite ratio on BiVO4 activity was also evaluated by degrading methyl orange in visible light.The results showed that the BiVO4 activity increased most when Bi2MoO6:BiVO4 were 5%(weight ratio),and the degradation rate of methyl orange was 55.2%after 50 min light irradiation.Compared with pure BiV04,degradation efficiency of Bi2MoO6/BiVO4 increased by 9.3%.The best photocatalyst dosage of methyl orange degradation of is 0.4g/L.2.AgVO3/BiVO4 composite photocatalysts with different composite ratios were prepared by hydrothermal method.The composite photocatalysts were characterized by XRD,SEM,EDS,XPS and UV-vis.The activity of composite photocatalysts was evaluated by degradation of methyl orange solution.The results showed that when the composite ratio of AgVO3 to BiV04 was 0.7:1,the activity of BiVO4 was the highest,and the degradation rate of methyl orange was 97.0%after 50 min light irradiation.,compared to pure BiVO4 increased by 79.4%.The best photocatalyst dosage of methyl orange degradation of is 0.15g/L.3.Firstly,Bi2MoO6 was prepared by hydrothermal method,then FeVO4 composite Bi2MoO6 photocatalyst was prepared by liquid-phase precipitation method and characterized by means of XRD,SEM,EDS,XPS and UV-vis,and the degradation of rhodamine B active.The results showed that when the ratio of FeVO4 to Bi2MoO6 was 3%(molar ratio),the activity of rhodamine B was the most obvious.The degradation rate of Rhodamine B was 64.5%in 50 min under visible light,which was 27.1%higher than that of Bi2MoO6.The optimum photocatalyst dosage of FeVO4/Bi2MoO6 to degrade rhodamine B was 0.15g/L.The results of the dissertation show that the photocatalytic activity of Bi2MoO6 and BiVO4 can be effectively improved by the semiconductor composite method.The main reason for the increase in the analytical activity lies in the fact that the photocatalytic activity of the photocatalytic material can be enhanced by capturing electron-hole and inhibiting recombination of the electron-hole.