Study of the mechanisms underlying the effects of composite intermediate layers on the performance of Ti/SnO2-Sb-La electrodes

Abstract

To mitigate the drawback of the short service life of titanium-based SnO2 electrodes, we prepared Ti/SnO2SbLa electrodes by the sol-gel method with two kinds of CeMn and FeMn composite intermediate layers, a Mn intermediate layer, or no intermediate layer. The surface structure and morphology of the prepared electrode coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), and the influence of the composite intermediate layer on the electrochemical performance of the electrode and the electrocatalytic oxidation of phenol were analysed by cyclic voltammetry, anodic linear voltammetry, AC impedance spectroscopy and Mott-Schottky curve tests; additionally, accelerated lifetime tests were performed for electrodes with different intermediate layers. The experimental results show that, compared to electrodes with the Mn interlayer or no intermediate layer, the electrode with the CeMn composite intermediate layer had markedly improved electrochemical performance and oxygen evolution potential, and the highest oxygen evolution potential could reach 1.84 V. Moreover, the capacity for electrocatalytic oxidation degradation of phenol was enhanced to some degree, with the highest removal rate of phenol reaching 93.6% after treatment for 180 min, and the maximum removal rate of COD can reach 77.92%. In the process of degrading phenol, the cell voltage of the electrode is kept to a minimum, and the stability is maximized. Accelerated lifetime testing showed that, compared with that of the no-intermediate-layer electrode, the lifetime of the electrode with the CeMn composite intermediate layer was increased 5-fold, with the longest lifetime reaching 85 min. Therefore, the CeMn composite intermediate layer can effectively improve the service life of electrodes based on titanium and tin.