Mechanism of an Elementary Act and the Kinetics of the Cathodic Evolution of Hydrogen
It has been mentioned above (see section 4.5) that in the case of hydrogen evolution in acidic solutions, the isotope separation factor depends considerably on the cathode potential. This was explained by the fact that the hydronium ion is attracted towards the electrode by the electric field. Naturally, this effect depends on the strength of the field which acts on the ion. Incidentally, irrespective of the mechanism by which the potential influences the isotope effect, the latter must directly depend not on the total metal solution potential drop, but on the potential difference between the metal and site at which the discharging ion is located. Hence, for different electrolyte solutions with different double-layer structures, the same isotope effect will be observed for identical values of φ - ψ1, where ψ1 is the local potential at the site of the discharging ion.
KeywordsHydrogen Evolution Isotope Effect Adsorbed Hydrogen Cathodic Reaction Reorganization Energy
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