Kinetic analysis of the hydrogen oxidation reaction at Nafion film covered Pt-black rotating disk electrodes

Abstract

The kinetics of the H₂ oxidation reaction at Nafion film covered Pt-black rotating disk electrodes (RDEs) in 0.5 M H₂SO₄ at 298 K was investigated by varying the Pt loading, Nafion film thickness, and rotating rate. The equation describing the H₂ oxidation kinetics at an RDE with a Nafion film covered porous Pt layer was derived, assuming a Tafel–Volmer mechanism and taking into account the mass transfer resistances in the aqueous electrolyte, Nafion film, and Pt layer. The H₂ oxidation reaction at the Pt layer was proved to be reversible and the measurable current density was determined entirely by the mass transfer of H₂ in the aqueous electrolyte and the Nafion film; the apparent kinetic current density measured was due to the experimental error. More accurate results of kinetic analysis were obtained in this work than our results reported previously.