Oxygen evolution and corrosion behavior of Pb-CeO2 anodes in sulfuric acid solution

Abstract

Pb-CeO2 composite anodes with different CeO2 contents were prepared by a powder metallurgy method. For comparison, pure Pb and Pb-Ag (0.8 wt%) anodes were also prepared as references by melt casting. The oxygen evolution and corrosion behaviors of the anodes were evaluated by performing measurements of galvanostatic polarizations, Tafel curves, anodic polarization curves, mass increments, and ion concentrations. The morphologies and phase compositions of the anode oxidation layers after polarization were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results showed that as the content of CeO2 increased, the stabilized potential of the composite anodes gradually decreased; the Pb-CeO2 (>1.5 wt%) composite anode exhibited lower stabilized potential and higher electrocatalytic activity than the Pb-Ag anode during galvanostatic polarization. The Pb-CeO2 (>0.5 wt%) composite anode showed better corrosion resistance than the pure Pb and Pb-Ag (0.8 wt%) anode. The increase in CeO2 content improves the compactness and thickness of the oxide layer formed on the anode surface, but excess CeO2 leads to high porosity of the anode, thus deteriorating the performance. The Pb-CeO2 (2.5 wt%) anode showed comprehensively improved electrochemical performance and corrosion resistance.