Electrocatalytic activity of ruthenium for oxygen reduction in alkaline solution

The electrochemical behavior and the electrocatalytic activity of ruthenium electrode for oxygen reduction are examined using cyclic voltammetry and r otating ring-disk electrode techniques. A surface oxide film on ruthenium m etal is formed when the potential is scanned in the positive direction of h ydrogen adsorption and evolution region. This oxide him affects the activit y of ruthenium for oxygen reduction reaction. Oxygen reduction on ruthenium electrode proceeds primarily by a direct 4-electron reduction pathway with out producing significant amounts of solution phase peroxide. The kinetic r esults suggest the initial electron transfer as the rate-determining step. (C) 2000 Elsevier Science Ltd. All rights reserved.