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

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.