Preparation and characterization of PbO2 electrode and its application in electro-catalytic degradation of o-aminophenol in aqueous solution assisted by CuO-Ce2O3/γ-Al2O3 catalyst

The electrochemical degradation of o-aminophenol (OAP) in aqueous solution was investigated by galvanostatic electrolysis using PbO2 electrode as anode. The Ti/SnO2-Sb2O3/PbO2 anode was prepared by thermal decomposition and electro-deposition method, and was characterized by X-ray diffraction (XRD). The hydroxyl radicals electro-generated on anode were detected by fluorescence spectroscopy. The effects of initial pH and current density on the efficiency of the electrochemical degradation process were also studied. UV spectroscopy and chemical oxygen demand (COD) measurements were conducted to evaluate the removal effects of organic pollutants. The experimental results showed that the refractory organics in wastewater can be removed by pure electrochemical process, COD removal efficiency of 91.6% was obtained in 70 min at initial pH 11.0 and current density was equal to 50 mA cm−2. In order to improve the efficiency of degradation and accelerate the reaction rate, a novel catalyst, γ-Al2O3 supported Ce-doped CuO, was synthesized by impregnating process and was characterized by X-ray photoelectron spectroscopy (XPS). The catalyst exhibited excellent catalytic activity in the electro-catalytic degradation of OAP wastewater and the COD removal efficiency of 91.7% was obtained in 20 min under mild conditions. Finally, a hypothetical mechanism of electro-catalytic degradation was proposed.