Estimation of kinetic parameters for the hydrogen oxidation reaction on smooth platinum

QUAINO, PAOLA MONICA; GENNERO DE CHIALVO, MARIA ROSA; CHIALVO, ABEL CESAR

Thessaloniki, Grecia

Congreso; 55th Annual meeting of the International Society of Electrochemistry (ISE); 2004

The International Society of Electrochemistry

The evaluation of the kinetic parameters of the hydrogen oxidation reaction (hor) is difficult to carry out accurately because of the important contribution of the mass transfer process. Therefore, in order to estimate these parameters for the hor on Pt, the experimental results obtained on a rotating disc electrode were correlated with recently developed theoretical expressions of the dependence of the current I on overpotential (E) and rotation rate ω, for the Tafel-Heyrovsky-Volmer mechanism. Experimental determinations of the dependence I(E,ω) were carried out in sulfuric acid 0.5 M under a continuous and strong hydrogen bubbling in order to ensure a permanent saturation of the electrolyte solution. The rotation rate was varied in the range 1600 < ω/rpm < 8100. Slow potentiodynamic sweeps were applied in the overpotential range -0.01 < E/V < 1.6 at 25°C. The Levich-Koutecky diagram corresponding to the limiting currents at the different ω values was obtained . It is characterized by an origin intercept different from zero and equal to B = 0.3035 1/mA. The polarization resistance Rp was also determined in an overpotential region near zero for the different ω values.