Preparation,Modification And Photocatalytic Degradation Activity Of Iospropanol Of BiOBr Photocatalysts

The volatile organic compounds（VOCs）produced by human activity threat human health.Photocatalytic oxidation technology can deeply deal with VOCs.It can transform the VOCs into harmless CO₂ and H₂O under mild conditions.So photocatalytic oxidation technology has great potential in air purification.The traditional TiO₂ photocatalyst has some defects,such as low utilization of solar energy,high recombination rate of the photo-induced electro-hole pair and low mineralization rate in the field of air purification,which limit its application ranges.Among the new photocatalytic materials,BiOX（X=Cl,Br,I）has attracted a great deal of attention because of its special electronic structure,highly anisotropic layered structure,excellent light absorption and high chemical stability.In this paper,the photocatalytic activity of BiOBr was optimized with the assist of amino acid.BiOBr was prepared and modified under mild conditions to improve its ability on photocatalytic degradation of isopropanol.This paper analyzes the degradation mechanism and expands the application scope of BiOBr.The main results are summarized as follows:（1）The BiOBr nanosheets were prepared by using four kinds of amino acids（proline,glycine,arginine,glutamic acid）as surfactant at room temperature.The PL characterization shows that the photo-induced electron and hole separation efficiency of BiOBr prepared with the assist of amino acids increased significantly.The degradation of isopropanol under simulated sunlight shows that there are some differences in the photocatalytic properties of BiOBr prepared with the assist of different kinds of amino acids.Combined with the structure of amino acids,this paper analyzes the roles of different amino acids in the synthesis procedure of BiOBr.The amount of free amino groups and carboxyl groups has an important influence on the activity of BiOBr.The optimal amino acids are arginine and glutamic acid.（2）Based on the previous study,arginine was locked as the surfactant,and we changed the amount of arginine to modify BiOBr to synthesize Bi₂₄O₃₁Br₁₀0 by precipitation method at room temperature.This paper explained why the amount of arginine changed caused that the crystal structure of synthesized samples changed from BiOBr to Bi₂₄O₃₁Br₁₀.The BiOBr and Bi₂₄O₃₁Br₁₀0 catalysts were characterized by XRD,SEM,DRS,PL,BET and XPS.The two kinds of catalysts were applied to degrade isopropanol under simulate sunlight.Research results show that Bi₂₄O₃₁Br₁₀has higher efficiency in mineralizing IPA and has greater potential for air purification.The mechanism of isopropanol degradation on BiOBr and Bi₂₄O₃₁Br₁₀0 catalysts was analyzed by trapping agent experiment.