A study on electrical properties of thermally grown TiO2 film at the interface of Ti/RuO2–IrO2–TiO2 anode using Mott-Schottky and electrochemical impedance spectroscopy techniques

Abstract This work aimed to achieve optimal thermal oxidation parameters to create a TiO2 film with excellent electrical properties at the interface of Ti/RuO2–IrO2–TiO2 anode to increase the service life of this anode in chloride solution. TiO2 films were prepared on commercially pure titanium (CPT) using thermal oxidation process at temperatures of 450, 480, and 520 °C for 45, 90, and 180 min under normal and air blowing atmospheres. Mott-Schottky and electrochemical impedance spectroscopy (EIS) measurements were employed to study the electrical properties of these films. Based on the results, the sample subjected to a thermal oxidation process at 450 °C for 115 min under air blowing atmosphere had the highest defects density and, as a result, the highest electrical conductivity. To investigate the effect of optimal thermal oxidation parameters on service life of Ti/RuO2–IrO2–TiO2 anodes, an accelerated life test (ALT) was performed on an anode sample in a solution of 0.1 M NaCl with a current density of 2 A/cm2. The results of this test demonstrated that the production of Ti/RuO2–IrO2–TiO2 anodes with the optimal thermal oxidation parameters instead of the typical thermal oxidation parameters (480 °C, 60 min, and normal atmosphere) led to the enhancement of their service life by up to 30% in 0.1 M NaCl solution.