Hydrogen oxidation and evolution on platinum electrodes in base: Theoretical study

Electrode potential dependent activation energies for electron transfer have been calculated for the hydrogen evolution and hydrogen oxidation reactions on platinum in base using the local reaction center model and constrained variation theory. Comparison is made with previous calculations for these reactions in acid using the same approach and with experimental literature results for acid and base. The results of the calculations are consistent with the Tafel-Volmer mechanism for H-2 oxidation and a mixture of Tafel-Volmer and Heyrovsky-Volmer mechanism for H-2 evolution in basic electrolyte on platinum surfaces.