INFLUENCE OF MERCURY ADSORPTION ON HYDROGEN EVOLUTION AT PLATINUM AND PALLADIUM

Potentiodynamic I vs. E curves were recorded in order to investigate the influence of mercury adsorption on the activity of smooth Pt and Pd electrodes as well as Pd/Pd electrodes in the hydrogen evolution reaction. It was shown that both in acidic and in alkaline solutions the effect of Hg adatoms consists in an inhibition of the slow reaction step by the blocking of sites accessible to hydrogen adsorption.