Activated carbon materials were modified by generating several functional groups containing oxygen and/or nitrogen atoms on their surfaces. Surface properties of obtained carbon samples were investigated. The point of zero charge was determined by different methods. The catalytic properties of these materials in the decomposition of hydrogen peroxide and in the electrochemical reduction of dioxygen in aqueous electrolytes have been studied. The catalytic activity for O-2 reduction correlates with that for HO2- decomposition. A linear relationship was derived for the dioxygen reduction peak potential and the decomposition rate constant. Thus, the selection of active catalysts for the heterogeneous decomposition of HO2- is a good starting point for the design of a carbon-based oxygen cathode. (C) 2002 Elsevier Science B.V. All rights reserved.