Preparation of a high-performance composite PbO2 electrode from a new bath for p-chlorophenol oxidation

Abstract

A new bath (Pb(CH3COO)2, H2NSO3H, NaF, CeO2 and polytetrafluoroethylene emulsion (PTFE), noted as bath-II) was proposed to prepare a high-performance composite PbO2 (Ti/PTFEFCeO2PbO2-II). The electrochemical performance of Ti/PTFEFCeO2PbO2-II in p-chlorophenol oxidation was compared with that of Ti/PTFEFCeO2PbO2-I which was prepared from a conventional bath with some additives (Pb(NO3)2, HNO3, HF, CeO2 and PTFE, noted as bath-I). The results of cyclic voltammetry (CV) and chronoamperometry (CA) of the pretreated Ti substrate in the two baths indicated that bath-II not only had higher current efficiency but also had high production efficiency for the deposition of PbO2. X-ray diffraction (XRD) analysis revealed that the crystalline phases of the two electrodes were both β-PbO2 but their dominant growth orientations were different (101 and 301 for Ti/PTFEFCeO2PbO2-I, 211 for Ti/PTFEFCeO2PbO2-II). Scanning electronic microscopy (SEM) analysis showed that compared with Ti/PTFEFCeO2PbO2-I, Ti/PTFEFCeO2PbO2-II had a more compact and uniform surface. Electrochemical impedance spectroscopy (EIS) analysis in 0.5molL−1 sulfuric acid showed that the double layer capacitance of Ti/PTFEFCeO2PbO2-II was about 27 times larger than that of Ti/PTFEFCeO2PbO2-I, indicating that Ti/PTFEFCeO2PbO2-II might has bigger specific area. The degradation of p-chlorophenol (p-CP) revealed that the electrochemical oxidative performance of Ti/PTFEFCeO2PbO2-II was better than that of Ti/PTFEFCeO2PbO2-I. The accelerated electrolysis test indicated that the life of Ti/PTFEFCeO2PbO2-II was about 1.6 times longer than that of Ti/PTFEFCeO2PbO2-I, showing that Ti/PTFEFCeO2PbO2-II had an excellent performance in electrochemical stability.