516-519The processes of adsorption and absorption
of H atoms on silver electrode in alkaline media has been studied using cyclic voltammetry
(CV) and electrochemical impedance spectroscopy (EIS). The potential range in
the CV studies has been between -0.1 and -1.6 V /Ag-AgCl. In the first cycle,
two cathodic and three anodic peaks have been observed. The H atom electrosorption
current peak at ca. -0.6 V/Ag-AgCl, which appears at second cycle, is assigned to
hydrogen absorption states. Nyquist plots consist of two overlapping semi-circles
of variable diameters depending on the extent of the cathodic dc-potential offset.
Hydrogen absorption occurs simultaneously with the hydrogen evolution reaction
and competes with it. The H atoms are converted to H2 rather than being
sorbed into the polycrystalline Ag when the potential is more negative. These H
atoms in the bulk of Ag electrode can be removed only by heating the electrode on
flame