Fabrication and characterization of a novel PbO2 electrode with a CNT interlayer

Abstract

A novel PbO₂ electrode (marked as CNT–PbO₂) with a carbon nanotube (CNT) interlayer was prepared by electrophoretic deposition and electro-deposition. The surface morphology, structure, electrochemical activity and stability of the CNT–PbO₂ electrodes were characterized by scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ·OH production test, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), bulk electrolysis and accelerated life test. The results show that, compared with the traditional PbO₂ electrode, the CNT–PbO₂ electrodes electrodeposited β-PbO₂ outer layer above the CNT interlayer had a higher crystallinity. The CNT–PbO₂-5 min electrode had a higher active surface area and lower charge transfer resistance than traditional PbO₂, CNT–PbO₂-10 min, and CNT–PbO₂-15 min electrodes due to a large number of exposed CNTs. However, the CNT–PbO₂-10 min electrode exhibited a stronger ability of ·OH production, higher direct oxidation capacity for degradation of 4-chlorophenol (4-CP) and longer service lifetime than other electrodes, whose apparent rate constant for 4-CP degradation and service lifetime was 2.7 times and 1.7 times those of traditional PbO₂ electrode, respectively. Thus, the proposed CNT–PbO₂-10 min electrode in this study is a promising anode for the electrochemical oxidation of refractory toxic organic pollutants.