Experiments on the hydrogen evolution by hot electrons at activated silver top electrodes of metal/insulator/metal (MIM) junctions demonstrated the existence of a transient adsorbed hydrogen species at the silver electrolyte interface. In the present work we investigated the hydrogen evolution on Ag(111), Ag(100), smooth polycrystalline, and activated silver surfaces in neutral and acid electrolytes with the help of cyclovoltammograms and potentiostatic current transients after cathodic potential pulses. In neutral electrolytes the hydrogen overpotential of Ag(100) was found to be 90 mV more negative compared to Ag(111). No difference was found under acid conditions (pH = 1). After cathodic pulses a transient hydrogen oxidation reaction was observed for the first time on activated silver surfaces in neutral electrolytes. The dc resistance of Ag(100) thin film electrodes is very little influenced by the hydrogen evolution reaction, compared to the increase induced by the adsorption of perchlorate.

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