A new Co-doped PbO2 anode for copper electrowinning: Electrochemical and morphological characterization

Abstract

Anodic electrodeposition was used to create a high catalytic activity Co-doped PbO2 composite coating on Ti substrate, in order to reduce the overpotential and raising the electrocatalytic activity for oxygen evolution during the copper electrowinning process. The temperature, composition, and current density of the electrolyte were investigated in order to produce a composite anode with the best electrocatalytic behavior, stability, and efficiency in the electrowinning process. Scanning electron microscopy (SEM) was utilized to investigate the morphology of the coating, and electrowinning, cyclic voltammetry (CV), and the accelerated life time test (ALT) were employed to evaluate the electrodes' electrochemical behavior. The ideal conditions in this investigation involved 65 g.L−1 cobalt nitrate with a 5 mA.cm−2 current density at 65 °C for the electrodeposition of Co-doped PbO2 coating. Furthermore, the potential for oxygen evolution of the PbO2-CoOx anode was found to be approximately 180 and 220 mV lower than that of the PbO2 and Pb-Ca-Sn anodes, respectively, based on the results of the electrochemical test. The ALT test results showed that the PbO2-CoOx anode had a significantly lower initial cell voltage than the Pb-Ca-Sn and PbO2 anodes; however, this value increased after 165 h due to the anode's mechanical breakdown. The results showed that Cu electrowinning efficiency for Pb-Ca-Sn, PbO2, and PbO2-CoOx was 91.9 %, 98.4 %, and 100 % respectively.