Evaluation of the kinetic parameters of the hydrogen electrode reaction from the dependence of the polarisation resistance on the hydrogen pressure

J.L. FERNÁNDEZ; M.R. GENNERO DE CHIALVO; A.C. CHIALVO

Sao Pedro

Congreso; 54th Annual Meeting of the International Society of Electrochemistry; 2003

International Society of Electrochemistry

The experimental determination of the kinetic parameters of the elementary steps involved in a given mechanism for the hydrogen electrode reaction (HER) is currently carried out through the evaluation of the dependence of the current density on overpotential in the range of high overpotentials. This experimental dependence can be obtained for both the hydrogen evolution reaction (her) and the hydrogen oxidation reaction (hor). On these conditions, the rate of a given elementary step is controlled by the rate of the forward reaction, as the contribution of the backward reaction is less significant. The purpose of the present work is to obtain the kinetic parameters for the HER on the basis of the dependence of the polarisation resistance on the hydrogen pressure. Near the equilibrium potential the forward and backward reaction rates of an elementary step are both significant and therefore all the kinetic parameters can be more appropriately evaluated.