Oxygen reduction and hydrogen evolution-oxidation reactions on Cu(hkl) surfaces

Taking advantage of the ring collection properties of the rotating ring-disk electrode with a single-crystal copper disk, we have shown that the oxygen reduction reaction and the hydrogen evolution-oxidation reactions on Cu(111) and Cu(100) surfaces in sulfuric acid are structure-sensitive processes. An interpretation of the structural sensitivity is presented, based on the premise of the structure-sensitive adsorption of (bi)sulfate anions. We have observed that the ordering kinetics of the (bi)sulfate on Cu(hkl) have an important rule in the mechanism of the oxygen reduction reaction. (C) 2000 Elsevier Science S.A. All rights reserved.