| PbO2 electrode, which has high electro-catalytic activity, chemical inertness, low cost and high oxygen overpotential is considered as a promising electrode material used in the electrochemical oxidation degradation of organic waste water. In this work, the PbO2 electrode was modified and the electrochemical oxidation degradation of organic waste water was studied with the PbO2 electrodes. The main research work and results was summarized as follows:The SnO2-Sb2O3 interlayer of lead dioxide electrode was prepared by thermal decomposition and PbO2 active coating was prepared by anodic electrodeposition. The surface morphology, crystal structure and element composition of the electrode were investigated by SEM, XRD and EDS. The study of service life was performed by accelerated life test. The results show that the SnO2-Sb2O3 intermediate layers bright obvious improvement in the service life of the PbO2 electrodes. Thus the compact SnO2-Sb2O3 layers may effectively slow down the diffusion of oxygen toward matrix and prevent the formation of TiO2 on Ti substrate.PbO2 electrodes co-doped with Ce and PVP were prepared by the electrodeposition. Scanning electron microscope (SEM), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) techniques were utilized to research the surface morphology, crystal structure, surface element composition and elemental states of the modified PbO2 electrodes. The electrochemical properties and lifetime of the modified electrodes were characterized by electrochemical techniques such as CV, EIS. Compared with other electrodes (Ti/SnO2-Sb2O3/PbO2 electrode, Ti/SnO2-SB2O3/PVP-PbO2 electrode and Ti/SnO2-Sb2O3/Ce-PbO2 electrode), PbO2 electrodes co-doped with Ce and PVP have higher removal rate of methyl orange and COD, in the process of degrading simulative dyeing waste water of methyl orange. The results showed that the electrode co-doped with Ce and PVP (Ti/SnO2-Sb2O3/PVP-Ce-PbO2) had the best degradation efficiency under the condition with current density of 50 mA-cm-2, pH of 5 and electrolyte concentration of 0.05 mol·L-1.The removal rate of 100 mg·L-1 methyl orange reached 98.4% and its COD removal value declined to 91.8% after degradation for 120 min. SEM showed that Ti/SnO2-Sb2O3/PVP-Ce-PbO2 electrodes had clearer particles and larger surface that significantly improved the microstructure and catalytic effects of the electrode. The results of electrochemical performance test demonstrated that Ce and PVP doping can increase oxygen over-potential of PbO2 and decrease charge transfer resistance.During eletrodepositing lead dioxide, electro-catalytic activity and stability of the electrodes could be significantly enhanced by adding some foreign ions or fine particles into the electrolyte. In this paper, β-PbO2 top layer of the electrode was prepared by electrodeposition with adding Nano-grade TiO2 and Ce in plating solution. SEM, XRD, EDS, XPS, EIS, CV and accelerated life test techniques were utilized to research the surface morphology, crystal structure, surface element composition, elemental states, electrochemical properties and service life of the PbO2 electrodes. Results show that the properties of the modified electrodes are improved and the modified electrodes with combined TiO2 and Ce display the best properties. SEM images and XRD patterns show that the surface morphology of the modified electrode has changed to varying degrees, while the crystal form of PbO2 is still β-PbO2. Results of EDS suggest that TiO2 and Ce may enter into PbO2 surface layer. Degradation experiments of methyl orange suggest that the modified electrode exhibits better electro-catalytic activity. Further studies of the electrochemical experiments indicate that the modified electrodes reveal lower charge transfer resistance and higher oxygen evolution potential. Additionally, accelerated lifetime tests exhibits that the electrode modified with TiO2 and Ce has longer lifetime and better corrosion resistance. |
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