Fabrication and characterization of β-PbO2/α-PbO2/Sb-SnO2/TiO2 nanotube array electrode and its application in electrochemical degradation of Acid Red G

A novel beta-PbO2/alpha-PbO2/Sb-SnO2/TiO2 nanotube array electrode was fabricated and investigated for the treatment of Acid Red G (ARG) in aqueous solution. Microwave and electrodeposition methods were employed for the deposition of Sb-SnO2 and PbO2 on the TiO2 nanotube array template, respectively. The structure and surface morphology of the composite electrode were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). Electrochemical measurements including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and accelerated life measurements were employed to investigate the electrochemical activity and stability of the hybrid electrode. The obtained composite electrode had an ordered multilayer structure with the TiO2 nanotube array serving as a tubal template and the Sb-SnO2 coating as an interlayer, and exhibited an enhanced electrocatalytic activity, long lifetime (815 h) and high oxygen evolution reaction potential. Acid Red G (ARG) was employed as a model organic pollutant for electrochemical degradation to evaluate the electrocatalytic activity of the composite electrode. Several operation variables, such as initial concentration, current densities, initial pH values, temperature of electrolyte, and chloride ions were investigated to explore the removal efficiency of ARG. It was found that low concentration, high current densities and addition of chloride ions could significantly improve the colour removal efficiency. Nevertheless, variables of pH and temperature had little impact on the colour removal efficiency. These results show that the hybrid electrode may become a promising electrode in treating wastewater.