Kong Y.,Kunming University of Science and Technology |
Kong Y.,State Key Laboratory Breeding Base Of Complex Nonferrous Metal Rsrc Cleaning Utilization In Yunnan Prov |
Xu R.,Kunming University of Science and Technology |
Xu R.,State Key Laboratory Breeding Base Of Complex Nonferrous Metal Rsrc Cleaning Utilization In Yunnan Prov |
And 5 more authors.
Cailiao Yanjiu Xuebao/Chinese Journal of Materials Research | Year: 2012
Pb-0.3%Ag/Pb-Co3O4 composite inert anodes were prepared on the surface of Pb-0.3%Ag substrates, the electrochemical properties of the composite inert anodes obtained under different forward pulse average current densities from 2 A/dm2 to 5 A/dm2 and different Co3O4 concentrations from 10 g/L to 40 g/L in bath were investigated. The anodic polarization curves, cyclic voltammetry curves and Tafel polarization curves were measured in a synthetic zinc electrowinning electrolyte of 50 g/L Zn2+ and 150 g/L H2SO4 at 35°C, the kinetic parameters of oxygen evolution, voltammetry charge, corrosion potential and corrosion current were obtained. The results show that Pb-0.3%Ag/Pb-Co3O4 composite inert anode obtained under forward pulse average current density of 3 A/dm2 and Co3O4 concentration of 30 g/L in bath, possess higher electrocatalytic activity, lower overpotential of oxygen evolution, better reversibility of electrode reaction and corrosion resistance in a synthetic zinc electrowinning electrolyte. The overpotential of oxygen evolution of the composite inert anode is 0.891 V under 500 A/m2, and it is 280 mV lower than that of Pb-1%Ag alloy; the surface voltammetry charge qz.ast; is 0.725 C·cm-2, and is 26.5% higher than that of Pb-1%Ag alloy; the corrosion current is also lower than that of Pb-1%Ag alloy. Large active surface areas and active substance numbers on the surface of the composite inert anode improve the electrocatalytic activity for oxygen evolution in [ZnSO4+H2SO4] solution. Fine and uniform grains, compact microstructures and fewer surface defects increase the corrosion resistance of the composite inert anode. © right.