铅合金电极在草酸电还原过程中的电化学性能

Electrochemical Properties of Lead Alloy Electrode in Reduction of Oxalic Acid

制成了Pb Cd Sb Ag〔w(Cd=2 0%),w(Sb)=1 0%,w(Ag)=0 015%〕四元铅合金,采用XRD、循环伏安、准稳态极化曲线、恒电位阶跃等方法研究了其物相及草酸电还原过程中的电化学行为。结果表明,自制的铅合金仍具有纯铅的晶体结构,其晶胞参数由于掺入较小原子半径的合金元素而变小,硬度却提高了70%。铅合金电极在草酸电还原反应中的交换电流密度为2 30mA/cm2,还原峰电位约-1 205V,与纯铅阴极相比,正移70mV;当电极电位在-1 25V时,电流效率可达91%。

A kind of lead alloy with the composition Pb-Cd-Sb-Ag〔w(Cd=2.0%),w(Sb)=1.0%,w(Ag)=0.015%〕was prepared.The sample was analyzed and characterized by XRD,cyclic voltammetry,quasi-steady-state polarization and chronoamperometry.The results demonstrated that the as-prepared lead alloy had the same crystalline structure as pure lead,while the cell parameter was decreased by adding Cd,Sb and Ag.The hardness of lead alloy is 70% higher than that of pure lead.The exchange current density of oxalic acid reduction at lead alloy electrode was 2.30 mA/cm^2.In comparison with pure lead cathode,the peak potential of oxalic acid reduction was shifted positively from -1.275 V on pure lead to -1.205 V on lead alloy electrode,and the maximum current efficiency of 91% was achieved at -1.25 V on lead alloy electrode.