RELATION BETWEEN NICKEL CRYSTALLINE-STRUCTURES AND THEIR ELECTROCATALYTIC PROPERTIES .3. STEADY-STATE OXIDOREDUCTION CHARACTERISTICS OF HYDROGEN ON NI

Anodic and cathodic steady curves corresponding to the reaction 2H2O+2 eH2+2OH- were plotted for vacuum deposited nickel electrodes. By referring to the number of sites calculated for Hads on different electrode structures, it has been found, that the different states of activity are consecutive to the variation of the number of adsorption sites. Moreover, from the analysis of the anodic limiting currents it can be shown that the classical step of the kind of H2 ag2Hads is unlikely and that a preliminary step like H2 H2,ads may occur. Cathodic curves analysis shows that the slow step is H2O+e→OH-+Hads and that Hads coverages are lower than 0.1 for overvoltages lower than 0.3 V. © 1979 Elsevier Sequoia S.A.