TIME-RESOLVED INVESTIGATION OF THE HYDROGEN EVOLUTION REACTION ON AG(111), AG(100), SMOOTH POLYCRYSTALLINE, AND ACTIVATED POLYCRYSTALLINE SILVER SURFACES

Experiments on the hydrogen evolution by hot electrons at activated si lver top electrodes of metal/insulator/metal (MIM) junctions demonstra ted the existence of a transient adsorbed hydrogen species at the silv er electrolyte interface. In the present work we investigated the hydr ogen evolution on Ag(lll): Ag(100), smooth polycrystalline, and activa ted silver surfaces in neutral and acid elec trolytes with the help of cyclovoltammograms and potentiostatic current transients after cathod ic potential pulses. In neutral electrolytes the hydrogen overpotentia l of kg(100) was found to be 90 mV more negative compared to Ag(lll). No difference was found under acid conditions (pH = 1). After cathodic pulses a transient hydrogen oxidation reaction was observed for the f irst time on activated silver surfaces in neutral electrolytes. The de resistance of Ag(100) thin film electrodes is very little influenced by the hydrogen evolution reaction, compared to the increase induced b y the adsorption of perchlorate.