A study has been made on the consecutive adsorption of CO/H-2 gases on Pt/SiO2 catalysts at 523 K using breakthrough measurements. The criteria for dispersion, diffusion and change in the pore size is evaluated and discussed as well as the equilibrium kinetic curves, which show to what extent the rates of sorption of one of the gases is affected by the presence of the other. The changes in average pore radii, surface areas and pore volume were very well estimated and correlated well with the breakthrough data.