Preparation and Characterization of PbO₂-CeO₂Nanocomposite Electrode with High Cerium Content and Its Appplication in the Electrocatalytic Degradation of Malachite Green

Abstract

PbO2-CeO2 nanocomposite electrodes were prepared by composite electrodeposition method in the lead nitrate solution containing CeO2 nanoparticles. The composite electrodes possess 8.79 at% cerium content, which is 12 times than the Ce-doped PbO2 electrodes (0.7 at%). The electrochemical measurements show that PbO2-CeO2 nanocomposite electrodes possess higher oxygen evolution overpotential (1.98 V vs. SCE) than PbO2 electrodes (1.51 V vs. SCE) and Ce-doped PbO2 electrodes (1.77 V vs. SCE). The service life of PbO2-CeO2 nanocomposite electrodes is 135 h, which is 1.8 times longer than that of Ce-doped PbO2 electrodes. The malachite green (MG) and chemical oxygen demand (COD) removal efficiency of PbO2-CeO2 nanocomposite electrodes reach 95.4% and 69.3%, respectively, after 90 min electrolysis in 0.2 mol L−1 Na2SO4 solution containing 30 mg L−1 MG with the current density at 30 mA cm−2 and pH values at 5.0. Compared with traditional PbO2 electrodes and Ce-doped PbO2 electrodes, PbO2-CeO2 nanocomposite electrodes possess highest COD removal efficiency and instantaneous current efficiency (ICE), and lowest specific energy consumption with MG degradation.