Preparation And Properties Of Cobalt Ion Co-deposited Lead Dioxide Composite Anode Materials

The Pb-(0.75?1.0)wt%Ag alloy anode is widely used in the Zinc electrodeposition industry,but it still has the deficiency of the high voltage,the poor conductive properties and the low mechanical strength.The new composite lead dioxide inert anode has attracted the attention because of its strong corrosion resistance,good electrical conductivity and so on.The electrodeposition behavior of ?-PbO2-CoOx was investigated by rotating disk electrode,and the optimum conditions of PbO2 synthesis were obtained.The Pb-Sn-Sb/?-PbO2/?-PbO2-CoOx composite inert anode materials were prepared by the composite electrodeposition technique under constant current conditions,and the deposition conditions were optimized by measuring the electrocatalytic activity and corrosion resistance.Finally,the electrochemical stability of the composite inert anode Pb-Sn-Sb/?-PbO2/?-PbO2-CoOx was tested in the simulation zinc electrowinning electrolyte.The main conclusions are as follows:The amount of ?-PbO2 reaches to the maximum when the solution was consist of 15 g·L-1 HN03,200 g·L-1 Pb(N03)2 and 30 g ·L-1 Co(N03)2·6H20 at 30 ?.The suitable deposition current density should be controlled at 0.006 A·cm-2.The Co-doped PbO2 has a more uniform morphology and smaller crystal size than pure PbO2.When the Co(NO3)2·6H2O concentration was 40 g·L-1,the concentration of Pb(NO3)3 was 200 g·L-1,the deposition temperature was 30 ? and the deposition current was 0.04 A·cm-2 in the acidic solution,the Pb-Sn-Sb/?-PbO2/?-PbO2-CoOx composite anode in the simulation zinc electrowinning electrolyte has the highest electrocatalytic activity for oxygen evolution and the strongest corrosion resistance.With the increasing of the concentration of Co(NO3)2·6H2O in the acidic bath,the grain size of ?-PbO2 becomed smaller,and Co2+ co-deposition ?-PbO2 could improve the section microhardness and electrode surface hardness of ?-PbO2 deposited layer.The steady-state oxygen evolution potential of Pb-Sn-Sb/?-PbO2/?-PbO2-CoOx composite anode were tested under 500 A·m-2 in the simulation zinc electrowinning electrolyte,which was 1.81 V and was 0.06 V lower than Pb-0.8wt%Ag alloy anode.The cell voltage was 2.9 V,which was 0.4 V lower than Pb-0.8wt%Ag alloy anode.The current efficiency was 92.6%,which was higher than Pb-0.8wt%Ag alloy anode.And the power consumption was 2567.0 kW·h·(t·Zn)-1,which was reduced by 387.7 kW·h·(t·Zn)-1 compared than Pb-0.8wt%Ag.The failure time of life was tested at high current densities(2000 A·m-2),which was about 19 hours.