Modified Preparation And Performance Research Of Bi₂WO₆ Photocatalyst

Photocatalytic technology as a new technology capable of solving water environment pollution has received wide attention from researchers in recent years.The band gap width of Bi₂WO₆ photocatalyst with a perovskite sheet structure is suitable to be about 2.7 e V,which can make good use of sunlight and has good stability,thus showing a good industrial application prospect.In this paper,morphology control,ion doping,and semiconductor recombination were used to modify the Bi₂WO₆ photocatalyst to improve its photocatalytic activity for degrading Rh B in dye wastewater.A series of characterization methods were used to analyze the morphology,structure and photocatalytic performance of the prepared samples,which is of great significance for China to solve the increasingly serious water pollution problem.The main contents and conclusions of the research of Bi₂WO₆ photocatalyst in this paper are as follows:1.Inorganic halogen salts?KF,KCl,KBr,KI?and surfactants?PVP,CTAB,SDS,SDBS?were used to modify the Bi₂WO₆ photocatalyst,and the morphology and structure of the prepared photocatalysts were analyzed by XRD,SEM,and BET.Finally,the photocatalytic degradation of Rh B was used to evaluate the photocatalytic activity of the photocatalysts.The results show that the photocatalytic activity of photocatalysts modified by inorganic halogen salts and surfactants in a certain period of time are significantly improved compared with that before modification.At the same time,through a series of characterization methods,it can be considered that the addition of inorganic halogen salts in the modification process will cause the modified Bi₂WO₆ photocatalysts to exhibit a nanosheet flake structure,and the specific surface area will increase significantly.The addition of surfactants make the morphology of the modified samples more uniform,and the surfactants can play a good role in spatial confinement and control the size of the nanomaterial.2.For the first time,a simple one-step solvothermal method was used to synthesize the hollow microspherical Cl-Bi₂WO₆ nanophotocatalyst with large specific surface area by utilizing the electrostatic adsorption of anions and cations in KCl and PVP.At the same time,EDS and XPS characterization results indicate the successful introduction of Cl^-in the hollow microspherical Bi₂WO₆ lattice.The successful introduction of Cl^-reduces the photogenerated electron-hole recombination efficiency of the photocatalyst.The photocatalytic degradation experiment showed that the photocatalytic degradation rate of the modified photocatalyst was improved by 12%than that before the modification within 60 minutes and the stability was good.The photocatalytic activity of the hollow microspherical Bi₂WO₆ photocatalyst prepared by this method is significantly improved.The results presented here provide a simple,effective,and widely applicable approach for the rapid synthesis of special morphology Bi₂WO₆ by a one-step method.3.Taking Cl-Bi₂WO₆ as the research object,the photocatalytic performance of Cl-Bi₂WO₆ photocatalyst was improved by compounding g-C₃N₄.In the research in this chapter,an ultra-thin g-C₃N₄ nanosheet with a thickness of about 8 nm was prepared by an improved ultrasonic stripping method.The ultra-thin g-C₃N₄ nanosheet with large specific surface area was then combined with Cl-Bi₂WO₆ to form a Z type heterostructure composite photocatalyst which can effective separate photogenerated electrons and holes.The related properties of the prepared Cl-Bi₂WO₆/g-C₃N₄ composite photocatalyst were characterized and discussed by XRD,TEM,FTIR,XPS,UV-Vis DRS,BET and other characterization methods.The experimental results of degradation of Rh B under visible light showed that the novel Cl-Bi₂WO₆/g-C₃N₄ heterostructure composite photocatalyst has a further improved photocatalytic activity compared with Cl-Bi₂WO₆.At the same time,when the composite amount of g-C₃N₄ is 60%and the catalyst addition amount is 2 g/L,the degradation rate of the composite photocatalyst can reach 99.2%within 40 minutes.The free radical capture experiments proved that the main active species of the prepared composite photocatalyst in the degradation of rhodamine B were·O₂^-and·OH,and a possible photocatalytic mechanism was proposed.