Fabrication Of Co And Ni-doped Zno Photoanode By Liquid Phase Deposition For Photoelectrocatalytic Degradation Of Antibiotics Under Visible Light

In this thesis,we prepared ZnO films and transition metal doped ZnO films by liquid phase deposition as photoanode for Photoelectrochemical degradation of antibiotic pollutants.The surface morphology,crystal structure,photoelectrochemical properties of undoped ZnO and doped ZnO thin films were characterized with various characterization methods.The main contents include the following two parts:1.We successfully deposited Co-ZnO thin film electrodes via the one-step liquid phase deposition(LPD).In this system,we established a traditional three electrode system for catalytic degradation of ofloxacin(OFL).Compared with ZnO thin film as working electrode,the degradation effect of ofloxacin was obviously improved by using Co-ZnO film electrode as photo anode.In addition,we systematically discussed the effect of Co concentration on the removal rate of ofloxacin.The degradation efficiencies of OFL by four different ways including direct photolysis(DP),photocatalysis(PC),electrochemical oxidation(EC)and photoelectric catalysis(PEC)were compared.The ZnO and Co-ZnO films were characterized by various instrumental analytical techniques such as scanning electron microscopy(SEM),X-ray diffraction(XRD),X-ray photoelectron Spectroscopy(XPS),UV-visible diffuse reflectance spectroscopy(DRS),photoluminescence spectroscopy(PL)and cyclic voltammetry(CV).Compared with pure ZnO film electrode,the Co-ZnO film electrode showed higher photocurrent and PEC activity for OFL removal under visible light illumination.The results indicate that Using the optimum 7.5% Co-doped ZnO film electrode,86.7% of OFL could be removed after 6-h PEC treatment under visible light illumination,and PEC is the most effective method for OFL degradation.Furthermore,the major intermediate products during the PEC process of OFL were identified by high-performance liquid chromatography-mass spectrometry;and a possible degradation mechanism for OFL on the Co-ZnO film electrode was proposed.2.In this system,we successfully prepared Ni-ZnO doped thin film electrode by one-step liquid-phase deposition.The Ni-ZnO film electrode was used as the photoanode with applying +0.8 V potential under the visible light for degradation of tetracycline(TC).In the experiment,the effects of ZnO and Ni-ZnO film electrodes on the removal rate of tetracycline were compared.Compared with undoped ZnO film electrode,the Ni-ZnO film electrode showed higher PEC activity for TC removal.The properties of ZnO and Ni-ZnO films were characterized with various characterization methods.It was proved that Ni was successfully entered into ZnO lattice,and it was found that the visible light photoelectrochemical activity of ZnO film electrode was obviously improved by Ni doping.