This text describes the production of polycrystalline titanium dioxide layers by anodic spark deposition (ASD). These deposits show an interesting electrochemical and electrocatalytic behaviour. A reversible electrochemical transformation of the crystalline phases could be proved. Furthermore, the TiO2-layers were used as electrode material for the cathodic reduction of molecular oxygen. In this process, cyclic voltammetry was employed, and the reduction of oxygen was successfully examined in dependence on surface-determining parameters such as layer thickness and pH value. (c) 2006 Elsevier Ltd. All rights reserved.