Hydrogen electrode reaction: a general description of the equilibrium polarization resistance

C. A. MAROZZI; M. R. GENNERO DE CHIALVO; M. A. MONTERO; A. C. CHIALVO

Buenos Aires

Congreso; 20th Topical Meeting International Society of Electrochemistry; 2017

The equilibrium polarization resistance is an experimental parameter that contains valuable kinetic information and can be evaluated directly and precisely. On metal electrodes the hydrogen electrode reaction (HER) is verified in both, alkaline and acid solutions, through the mechanism of Volmer-Heyrosky-Tafel (VHT). It shows a strong diffusion contribution of the molecular hydrogen in the anodic potential region, which turns to be negligible for cathodic overpotentials lower than -0.15 V, being significant around equilibrium potential. Moreover, Rp is widely used to evaluate the exchange current density (jo), although it is distorted by the diffusion contribution.