ON THE DETERMINATION OF KINETIC-PARAMETERS OF THE HYDROGEN EVOLUTION AT HIGHLY-ACTIVE PT-ELECTRODES BASED ON POTENTIAL DECAY CURVES

The kinetics and the mechanism of the hydrogen evolution at highly act ive Pt electrodes was determined on the basis of potential decay curve s. The rate constants of the Volmer-, Heyrovski- and Tafel-reactions w ere determined by solving a system of differential equations in accord ance with the model of Harrington and Conway The calculated rate const ants which fit the potential decay and the current potential curves be st were taken as the real ones. The results show that the rates of the Volmer- and the Heyrovski-reactions are of the same magnitude. The ra te of the Tafel-reaction is very low in comparision with the Volmer- a nd the Heyrovski-reactions and plays no role in the hydrogen evolution under the conditions of our experiment. The quantity of adsorbed hydr ogen exceeding a monolayer is low, i.e,, there is no second layer of a dsorbed hydrogen.