Construction Of Bismuth-containing Heterojunction Films With Improved Visible-light Photoelectrocatalytic Activity

Photoelectrocatalytic technique is an efficient,green and sustainable advanced oxidation processes.The efficiency of the photoelectrocatalytic system depends on the properties of anode materials.In this thesis,we employed different methods to prepare BiVO4/ZnO and Bi2S3/Bi2O3/WO3 film.SEM(Scanning electron microscopy),XRD(X-ray photoelectron spectroscopy),EDS(Element dispersive spectroscopy),XPS(X-ray photoelectron spectroscopy),PL(Photoluminescence)and UV-Vis DRS(UV-visible diffuse reflectance spectroscopy)to analysis the morphology,crystal,elementary compositions and the chemical valence states,photo-absorption performance of as-prepared materials.The photoelectrocatalytic performances of the as-prepared films were investigated.The main contents of paper are as follows:A BiVO4/ZnO composite film was successfully fabricated via a combination of the liquid phase deposition technique and the successive ionic layer adsorption and reaction process(SILAR).The crystalline phases and morphologies of materials were examined.The results revealed wurtzite ZnO were irregular nanorods and monoclinic BiVO4 irregular nanoparticles were successfully formed in the composite film.Photoluminescence analysis revealed that BiVO4/ZnO film showed superior response to pure ZnO and BiVO4 films.The photocurrent,linear sweep voltammetric(LSV)and electrochemical impedance spectroscopy(EIS)analyses suggested the BiVO4/ZnO film showed higher visible-light photoelectrocatalytic(PEC)activity than did pure ZnO and BiVO4 films.The PEC activity of BiVO4/ZnO film was evaluated by the the degradation of tetracycline.In the PEC system of removing contaminants,visible light irradiation and the applied voltage of +1.0 V were used,the 2-h removal efficiency of tetracycline reached 66.1%,which 40% and 30.2% higher than ZnO and BiVO4,respectively.The trapping experiments implied the main active species was h+.2.A Bi2S3/Bi2O3/WO3 heterojunction film was fabricated by combination of reduction of tungstic acid peroxide,spin-coating and in-situ anion exchange under room temperature.Photoluminescence and Uv-vis DRS analysis revealed Bi2S3/Bi2O3/WO3 heterojunction film showed greater utilization efficiency of visible light,better separation efficiency of photogenerated holes and electrons and higher removal efficiency of contaminants.The fabricated Bi2S3/Bi2O3/WO3 film was applied to the photoelectrocatalytic(PEC)degradation of diclofenac under visible light illumination.After 3h-treatment,the decoloration efficiency of Rh B was 84.2%,the removal efficiency of diclofenac was 61.1%.