Browsing by Author "Burke, L. D."

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Oxygen Electrode Reaction: Part 2.—Behaviour at Ruthenium Black Electrodes
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (5), 1972) Burke, L. D.; O’Meara, T. O.
    Charging curves and cyclic voltammetry were used to investigate the nature of the interaction of oxygen with an active ruthenium surface. Rather vigorous corrosion was observed under highly anodic conditions and the products, which must involve ruthenium ions in a variety of oxidation states, gave rise to a rather unusual catalytic process for oxygen evolution. Although ruthenium can adsorb large quantities of oxygen, its performance as a substrate for the oxygen reduction process is not very promising. Comparison with the reported behaviour on metals such as gold and platinum suggests that while d-band vacancies are essential for oxygen chemisorption, the concentration of such vacancies in ruthenium is too great. The overall result is that considerable overvoltage is required for oxygen reduction as the tightly bonded oxide film on the metal surface can either inhibit the reduction of molecular oxygen, or be itself reduced, even in the presence of dissolved oxygen, at potentials strongly cathodic to the reversible oxygen potential.
  • No Thumbnail Available
    Item
    The Oxygen Electrode: Part 3,—Inhibition of the Oxygen Evolution Reaction
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (6), 1972) Burke, L. D.; McCarthy, F.; O’Meara, T. O.
    The anodic behaviour of water is discussed in terms of a model in which discharge occurs via a cation radical intermediate which rapidly loses a proton to yield potential-determining hydroxyl radicals on the metal surface. Hysteresis in the charging curves in the case of noble metal electrodes is explained in terms of an anodic stage involving the production of these hydroxyl radicals on the surface, and a subsequent cathodic stage involving (largely) the reduction of a layer of chemisorbed oxygen. Coverage of the electrode surface by hydroxide radicals is not at any time regarded as being very large as conversion to an oxide film occurs, possibly via a peroxide intermediate. Oxygen evolution is assumed to occur via a similar mechanism, the adsorbed peroxide intermediate being undetectable under normal conditions as peroxides arc instantaneously oxidized in the potential region in question. An attempt is made to account for the mechanism proposed for oxygen evolution, and other facets of oxygen electrochemistry, in terms of solvent electrostriction at the metalsolution interface at high positive potentials.