In this work an investigation of the hydrogen oxidation reaction at platinum and at platinum/polymer electrolyte interfaces in contact with aqueous solutions composed of mixtures of H2SO4 and K2SO4 (pH range of 0.2-7.5) was carried out. The studies were conducted using cyclic voltammetry, rotating disk electrode and potential step chronoamperometry. The results allowed the determination of the solubility and the diffusion coefficient of the hydrogen gas in the aqueous solutions and the permeability in the polymer electrolyte. Specific theoretical treatments were employed in order to allow the interpretation of the experimental data and to characterize the kinetic and the mechanism of the hydrogen oxidation reaction.