Effects of current density on preparation and performance of Al/conductive coating/a-PbO2-CeO2-TiO2/ß-PbO2-MnO2-WC-ZrO2 composite electrode materials

Al/conductive coating/a-PbO2-CeO2-TiO2/β-PbO2-MnO2-WC-ZrO2 composite electrode material was prepared on Al/conductive coating/a-PbO2-CeO2-TiO2 substrate by electrochemical oxidation co-deposition technique. The effects of current density on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated by energy dispersive X-ray spectroscopy (EDXS), anode polarization curves, quasi-stationary polarization (Tafel) curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Results reveal that the composite electrode obtained at 1 A/dm2 possesses the lowest overpotential (0.610 V at 500 A/m2) for oxygen evolution, the best electrocatalytic activity, the longest service life (360 h at 40 °C in 150 g/L H2SO4 solution under 2 A/cm2), and the lowest cell voltage (2.75 V at 500 A/m2). Furthermore, with increasing current density, the coating exhibits grain growth and the decrease of content of MnO2. Only a slight effect on crystalline structure is observed.