On stability of iodine doped TiO2 electrodes in pH varied aqueous electrolytes

New iodine doped TiO2 (I-TiO2) has been characterised as an electrode material in a form of a 2 μm thick layer on a Pt substrate in 0.5 M Na2SO4 aqueous electrolytes with pH varied from 7.7 to 3. Cyclic voltammetry and impedance spectroscopy measurements were carried out in order to determine the properties of the electrode/electrolyte interfacial properties. The flatband potentials Efb were evaluated from Mott–Schottky plots as a function of the electrolyte pH. The obtained Efb values for I-TiO2 are shifted anodically in comparison with the Efb of pure TiO2. The slope of the Efb vs. pH plot is equal to 58.4 mV/pH at 22 °C proving the good stability of the I-doped TiO2 in contact with a solution.