Preparation Of Bi₂WO₆-based/ACF Photocatalyst And Study On The Performance Of Toluene Oxidation

In today’s society,environmental pollution has become a serious obstacle to the development and progress of the society.Especially the treatment of VOCs in the atmosphere is an urgent problem to be solved.Traditional biochemical treatment and chemical treatment can no longer satisfy the needs of contemporary society,while the photocatalytic technology is clean,no two pollution,can use solar energy the advantages of by the majority of researchers pay great attention to.Because the band gap of TiO₂ semiconductor photocatalyst is wide（3.2e V）and the quantum efficiency is too low,limit its application in the field of photocatalysis.Therefore,the study of semiconductor materials with high activity and wide spectral light response is the main research direction of photocatalysis.In this paper,the Bi₂WO₆ precursor solution was prepared by the hydrothermal method.And on this basis,a series of C₃N₄/Bi₂WO₆,TiO₂/Bi₂WO₆ and Bi OI/Bi2WO6 composite photocatalysts have been prepared.The photocatalyst was uniformly loaded on activated carbon fiber felt（ACF）by impregnation method.The samples were characterized by XRD,SEM,TEM,XPS,BET and UV-Vis and investigated with toluene as the target pollutant.The reaction mechanism of catalyst and the discussion of the results of the study show that:The C₃N₄/Bi₂WO₆ composite samples prepared by hydrothermal method are all orthorhombic crystal structures.C₃N₄ interacts with Bi₂WO₆ lamellar structure,and the two closely contact to form heterostructures.The synthesized C₃N₄/Bi₂WO₆ material has larger specific surface area and lower band gap,which can effectively inhibit the recombination of photogenerated electrons and holes,increase quantum transfer efficiency and be more easily stimulated by light.When toluene concentration is about 500 mg/m³ and light intensity is 24W,40%mol C₃N₄/Bi₂WO₆/ACF has the best removal effect on gas-phase toluene,the removal rate can reach 58.1%,which is 1.83 times of monomer Bi₂WO₆.The TiO₂/Bi₂WO₆ prepared by hydrothermal method has a typical heterostructure.The TiO₂ is loaded on the surface of the Bi₂WO₆ lamellar structure,and the two are closely combined without destroying each other’s phase crystalline form.Compared with the monomer Bi₂WO₆,TiO₂/Bi₂WO₆ can effectively promote the separation of photogenerated electrons and holes,and has good visible light absorption properties.When toluene concentration was about550 mg/m³ and light intensity was 24 W,the removal efficiency of 30%mol TiO₂/Bi₂WO₆/ACF was the best.The removal rate was 50.37%,which was 1.6 times higher than that of monomer Bi₂WO₆.When the concentration of toluene is about 350 mg/m³ and the light intensity is 24 W,20%mol Bi OI/Bi₂WO₆/ACF has the best effect on removing gas-phase toluene.The removal rate can reach 76.33%,which is 2.4 times higher than that of monomer Bi₂WO₆.The sample prepared under this condition did not change the main phase of Bi₂WO₆.The composite of Bi OI and Bi₂WO₆ still formed orthorhombic crystal structure.Bi OI was dispersed on the surface of Bi₂WO₆.The good conductivity of Bi OI increased the number of active sites of the composite photocatalytic materials and promoted the separation of photogenerated carriers.