Hydrogen evolution at silver electrodes by hot electrons

Electrons within silver, with energies up to 2 to 3 eV above the Fermi level of silver, are formed in A1/A12O3/Ag tunnel junctions. These hot electrons may induce electrochemical reactions at the silver-electrolyte interface. When the silver surface is smooth, one observes only injection of hot electrons into the conduction band of the electrolyte, whereas hydrogen is developed at rough and activated silver surfaces: at electrochemical potentials where this is thermodynamically possible, but usually kinetically hindered. Intermediate ''wet electron'' states are not involved in this reaction. There is an evidence for a 60% atomic hydrogen coverage of silver during the hydrogen evolution reaction. (author)