Time Resolved Investigation of the Hydrogen Evolution Reaction on Ag(111), Ag(100), Smooth Polycrystalline, and Activated Polycrystalline Silver Surfaces

Abstract

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.

Role of Hot Electrons and Metal–Oxide Interfaces in Surface Chemistry and Catalytic Reactions

“…17,218 Diesing et al found that the hydrogen evolution reaction is promoted when a bias voltage is applied to the metal−insulator−metal junction. 72 The promotion of decomposition of chlorinated hydrocarbons by electron emission was observed by Sharpe et al 83 Bias voltage-induced decomposition of 2-methyl-1,4-naphthoquinone was observed by Wadayama et al on the MIM tunnel junction. 84 Wadayama et al used surface-enhanced Raman spectroscopy (SERS) to uncover the hot electron-induced surface reaction of p-nitrobenzoic acid (PNBA) adsorbed on a Ag top electrode in a Ag/AlO x /Al tunnel junction.…”

Study and preparation of silver electrodeposits at negative potentials

“…This clearly increased both when the pH of the blank solution was decreased and when solution was stirred. Then, the second reduction process detected during silver electrodeposition (peak II) was assigned to proton reduction [15].…”

“…The hydrogen evolution reaction on silver electrodes follows the Volmer-Heyrowski mechanism, in which H ads is formed as reaction intermediate, a prewave appearing in perchlorate medium corresponding then to H ads formation [15]. From our voltammetric results, we can deduce that 9.…”

Specific adsorption of phosphate species on Ag (111) and Ag (100) electrodes and their effect at low overpotentials of the hydrogen evolution reaction

“…The study of the onset potential of her as a function of pH on Ag(hkl) was first reported by Diesing et al by means of surface resistance measurements [19]. They have found that the two faces have the same onset potential of her in 0.1 M HClO 4 , but differ in neutral solution.…”