Analysis of the use of voltammetric results as a steady state approximation to evaluate kinetic parameters of the hydrogen evolution reaction

Abstract

The use of the voltammetric response jvol(η) of a potentiodynamic sweep at a slow scan rate vs in place of a steady state polarization curve jss(η) for the determination of the kinetic parameters of the hydrogen evolution reaction is analyzed. It is proposed to consider jvol(η, vs) ∼= jss(η) when the condition 0.99 ≤ jvol(η, vs)/jss(η) ≤ 1.01 is verified in the overpotentials range η≤−0.05V. It has been also established a simple relationship between the maximum admissible scan rate vmax s and the equilibrium polarization resistance Rp. Finally, the application of this criterion on different electrodes is described and discussed.