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采用循环伏安、线性扫描、电化学阻抗和环境扫描电镜对比研究了Pb-Ag和Pb-Ag-Nd阳极的阳极膜和析氧反应.结果表明,合金元素Nd促进了Pb/PbOn/PbSO4(1≤n<2)膜层的生长.在高极化电位区间(高于1.20V(vs Hg/Hg2SO4/饱和K2SO4溶液)),Nd有利于低价铅的化合物(PbOn,PbSO4)向α-PbO2和β-PbO2转变.此外,环境扫描电镜形貌和线性扫描分析证明Pb-Ag-Nd表面生成的阳极膜较Pb-Ag的阳极膜更厚且更致密.因此,Pb-Ag-Nd阳极表面的阳极膜可以给合金基底提供更好的保护.另一方面,电化学阻抗测试揭示了两种阳极的析氧反应均受中间产物的形成和吸附控制.Nd可以降低阳极膜/电解液界面处中间产物的吸附阻抗且增加中间产物的覆盖率,从而提高析氧反应活性.综上所述,合金元素Nd可提高Pb-Ag阳极的耐腐蚀性,降低阳极电位进而起到节能降耗的作用.
The anodic films and oxygen evolution reactions of Pb-Ag and Pb-Ag-Nd anodes were studied by cyclic voltammetry, linear sweep, electrochemical impedance and environmental scanning electron microscopy. The results show that alloying element Nd promoted the Pb / PbOn / PbSO4 (PbOn, PbSO4) favors the formation of a-layer at the high polarization potential (higher than 1.20V (vs Hg / Hg2SO4 / saturated K2SO4) PbO2 and β-PbO2. In addition, the morphology and linear scanning analysis of environmental scanning electron microscope confirmed that the anodic film formed on the surface of Pb-Ag-Nd was thicker and denser than that of Pb-Ag anode film. On the other hand, the electrochemical impedance test revealed that the oxygen evolution reaction of the two anodes were both controlled by the formation of the intermediate product and the adsorption control.Nd could reduce the anodic film / electrolyte interface At the intermediate product of the adsorption resistance and increase the coverage of intermediate products, thereby enhancing the oxygen evolution reaction activity.In summary, alloying elements Nd can improve the corrosion resistance of Pb-Ag anode, reducing the anode potential and thus play a saving energy effect.