A moment technique was developed for the investigation of adsorption on metal surfaces of supported catalysts. The technique was applied to the evaluation of adsorption rate parameters of CO on a Pt-Al2O3 washcoated monolith. The adsorption rate constants evaluated in the temperature range 273-316 K showed significant decrease with an increase in surface coverage. Results of pulse response experiments corresponding to zero coverage gave the apparent activation energy for adsorption as 21 kJ/mol. This method allowed the evaluation of adsorption rate constant on metal sw-faces at different coverages.