Study on the service life and deactivation mechanism of Ti/SnO ₂-Sb electrode by physical and electrochemical methods

The Sb doped tin dioxide electrode (Sb-doped SnO₂) inter-layer was prepared using electroposition layer-by-layer onto a titanium plate, and the Sb-doped SnO₂ surface catalytic layer (Ti/SnO₂-Sb) was prepared using thermo-decomposition method. Accelerated service life tests were carried out in 0.5 M H₂SO₄ solution and 1.0 M NaOH solution, respectively. The deactivation mechanism of the electrodes is studied using oxygen evolution reaction (OER) as the reaction mode. Cyclic voltammetry test showed that the electrodes after accelerated life tests had no catalytic-oxidizing activity upon phenol. Electrochemical impedance spectroscopy (EIS) analysis exhibited that the membrane resistance of the deactivated electrode increases obviously in 0.5 M H₂SO₄ solution and 1.0 M NaOH solution, with the values of 1231 and 90.6 Ω, respectively. The structure, morphology and the content of the fresh and deactivated electrode were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray detector (EDX). This suggested that the Ti content on the electrode surface increases after deactivation, and TiO ₂ membrane with poor conductivity is grown on the electrode surface.