Study of the hydrogen electrode reaction on Pt/Bi(ad) electrodes

P.M. QUAINO; 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 objective of the present work is to determine if the irreversible adsorption of Bi on Pt can take place on the sites occupied by the HOPD atoms. Therefore, the hydrogen electrode reaction (HER) was studied through the experimental determination of the dependence of the current (I) on overpotential (E), in the potential region near the equilibrium state. The working electrode was a roughness platinum wire, with roughness factors ranging between 20 and 40. The electrolyte solution was 0.5M H2SO4 saturated with hydrogen gas at 25°C. The purity of the solution was controlled through a slow potentiodynamic sweep applied after a cathodic potentiostatisation during 30 min. The adsorption of Bi was carried out at a controlled potential (-0.05 V < Ead < 0.05 V, vs. RHE) during different times (30 s < tad < 180 s). The amount of Bi(ad) was evaluated through the conventional method, from the fraction of surface inhibited by the HUPD atoms.