Influence of electrolyte composition on deactivation mechanism of a Ti/Ru0.25Ir0.25Ti0.5O2 electrode

Deactivation of a RuO2-IrO2-TiO2/Ti electrode was investigated during an accelerated life test in H2SO4 and NaCl solutions using cyclic voltammetry, electrochemical impedance spectroscopy, and SEM/energy dispersive spectroscopy. It is found that the deactivation mechanism depends on electrolyte composition. Intensive Ru/Ir dissolution from the oxide coating and the growth of an insulating TiO2 interlayer are the main deactivation mechanisms of anode in H2SO4 and NaCl solutions, respectively. The results indicate that the determining factor in deactivation mechanism is the morphology factor of oxide anode in different solutions which restrains the diffusion process of electrolyte into coating inner layers.