Preparation of a three-dimensional porous PbO2-CNTs composite electrode and study of the degradation behavior of p-nitrophenol

Abstract

• A new porous PbO 2 -CNTs electrode was prepared by oxygen bubble template method. • Porous PbO 2 -CNTs electrode has high electrocatalytic activity and stability. • P-nitrophenol was removed from water by porous PbO 2 -CNTs electrode. • The electrochemical degradation intermediates and pathway of p-nitrophenol were proposed. In this study, a new type of porous PbO 2 -CNTs electrode was prepared by the oxygen bubble template method to remove the organic pollutant p-nitrophenol in water. The electrode microscopic morphology, phase composition and element composition were characterized by physical methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). According to linear scanning voltammetry (LSV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), the 3D-PbO 2 -CNTs composite electrode shows a higher exchange current density, larger electrochemically active surface area and smaller charge transfer resistance than the 3D-PbO 2 and flat-PbO 2 -CNT electrodes. The 3D-PbO 2 -CNTs composite electrode was applied to the degradation of p -nitrophenol, and the results indicate that it has the strongest ability to generate hydroxyl radicals and the best electrocatalytic degradation efficiency. The degradation process follows pseudo-first-order reaction kinetics, and the intermediate products were characterized using GC–MS and a degradation mechanism for p -nitrophenol was proposed. From measurements of the cell voltage for degrading simulated phenolic wastewater, it was found that the battery voltage for the 3D-PbO 2 -CNTs composite electrode is 3.52 V, which is lower than that obtained for the 3D-PbO 2 (3.59 V) and flat-PbO 2 -CNTs (3.85 V) electrodes, indicating that the anode material is effective in reducing energy consumption. In general, the new 3D-PbO 2 -CNTs electrode has good application prospects in the field of degrading organic polluted wastewater.