Changes in the voltammetric response of titanium electrodes caused by potential programmes and illumination

The electrochemical behaviour of polycrystalline Ti electrodes was studied in dilute aqueous aIkaline solutions at 25 degrees C. Fast repetitive potential programmes (triangular and square waves) were applied to Ti electrodes to grow different O-containing films. The growth efficiency of Ti oxides principally depends on the upper potential limit of the corresponding program. Potentiostatic preillumination of Ti electrodes produces surface modifications that can be followed by cyclic voltammetry, Two types of photoactive surface sites are evidenced; one coinciding with the potential window of the photogenerated molecular oxygen electroreduction reaction, and the other resulting from the electroreduction of photoformed oxygenated radicals, The application of both potential programmes and illumination can change the electrochemical properties of Ti surfaces in alkaline solutions. (C) 1997 Elsevier Science Ltd.