Eu/GO/PbO2 composite based anode for highly efficient electrochemical oxidation of hydroquinone

Abstract

Herein, a novel europium/graphene oxide/lead oxide (Eu/GO/PbO2) composite based anode with excellent electrocatalytic performance towards degradation of hydroquinone was prepared by a facile co-electrodeposition method. The composition and micromorphology of the anode was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) and the results confirmed that europium (Eu) and graphene oxide (GO) were successfully composited with PbO2 and a more compact structure was obtained, which was conductive to enhancing the corrosion resistance of the electrode. Besides, electrochemical measurements indicated that Eu/GO/PbO2 electrode possessed longer service lifetime (87 h), higher oxygen evolution potential (2.64 V), and lower charge transfer resistance (41.08 Ω) than GO/PbO2 and pure PbO2 electrode. The promoted electrocatalytic activity of Eu/GO/PbO2 electrode was ascribed to its stronger hydroxyl radical generation ability, more active sites and lower electron transfer resistance. Additionally, effects of initial hydroquinone concentration, applied current density and initial pH value on the degradation performance of Eu/GO/PbO2 anode were systematically investigated. The behind degradation mechanism of hydroquinone by Eu/GO/PbO2 anode was speculated on the basis of the major intermediates identified by high performance liquid chromatography-mass spectrometer (HPLC-MS). Under the continuous attack of free hydroxyl radicals, hydroquinone was finally decontaminated into CO2 and H2O. The present work demonstrated that Eu/GO/PbO2 composite anode exhibited excellent degradation performance towards hydroquinone.