Modification of Ti/Sb-SnO2/PbO2 Electrode by Active Granules and Its Application in Wastewater Containing Copper Ions

Abstract

Active granule (WC/Co3O4) doping Ti/Sb-SnO2/PbO2 electrodes were successfully synthesized by composite electrodeposition. The as-prepared electrodes were systematically characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical performance, zeta potential, and accelerated lifetime. It was found that the doping of active granules (WC/Co3O4) can reduce the average grain size and increase the number of active sites on the electrode surface. Moreover, it can improve the proportion of surface oxygen vacancies and non-stoichiometric PbO2, resulting in an outstanding conductivity, which can improve the electron transfer and catalytic activity of the electrode. Electrochemical measurements imply that Ti/Sb-SnO2/Co3O4-PbO2 and Ti/Sb-SnO2/WC-Co3O4-PbO2 electrodes have superior oxygen evolution reactions (OERs) relative to those of Ti/Sb-SnO2/PbO2 and Ti/Sb-SnO2/WC-PbO2 electrodes. A Ti/Sb-SnO2/Co3O4-PbO2 electrode is considered as the optimal modified electrode due to its long lifetime (684 h) and the remarkable stability of plating solutions. The treatment of copper wastewater suggests that composite electrodes exhibit low cell voltage and excellent extraction efficiency. Furthermore, pilot simulation tests verified that a composite electrode consumes less energy than other electrodes. Therefore, it is inferred that composite electrodes may be promising for the treatment of wastewater containing high concentrations of copper ions.