New iodine doped TiO2 (I-TiO2) has been characterised as an electrode material in a form of a 2 mu m 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 E-fb were evaluated from Mott-Schottky plots as a function of the electrolyte pH. The obtained E-fb, values for I-TiO2 are shifted anodically in comparison with the E-fb, of pure TiO2. The slope of the E-fb vs. pH plot is equal to 58.4 mV/pH at 22 degrees C proving the good stability of the I-doped TiO2 in contact with a solution. (C) 2010 Elsevier B.V. All rights reserved.