Electrochemical Performance of a New Type Aluminum Foam/Pb-0.6 wt%Ag Alloy Composite Anode for Zinc Electrowinning Industry

Abstract

In order to overcome the defects of high over-potential and preparation cost existing in traditional Pb alloy anodes, a new type aluminum foam/Pb-0.6 wt%Ag alloy composite anode (AF/Pb-0.6 wt%Ag anode) was produced. The electrochemical performance of AF/Pb-0.6 wt%Ag anode and traditional Pb-0.6 wt%Ag anode after 72 h galvanostatic polarization in 160 g/L H₂SO₄ solution was investigated comparatively by chronopotentiometry (CP), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and Tafel measurements. The results show that the anodic layer of AF/Pb-0.6 wt%Ag anode is more intact than that of the Pb-0.6 wt%Ag anode, and exhibits better corrosion resistance. Moreover, the AF/Pb-0.6 wt%Ag anode shows a lower stable anodic potential, which is consistent with higher PbO₂, lower PbO, PbO·PbSO₄ content and R_ct value obtained by CP and EIS measurements. It is also revealed that the AF/Pb-0.6 wt%Ag anode possesses a better oxygen evolution reaction (OER).