Nanodispersed metallic clusters of platinum and palladium were incorporated into NaX zeolite cavities by impregnation with acetone solution of corresponding acetylacetonates, solvent evaporation and acetylacetonate thermal decomposition. The acetylacetonate decomposition was followed by thermogravimetry. Modified zeolite samples were characterized by x-ray diffractommetry. In order to get a satisfactory electronic conductivity of modified zeolite, 10% wt of carbon black was added. This material was applied to a rotating glassy carbon disc electrode, and was used to study electrochemical water splitting in slightly acidic aqueous solutions. Noble metal modified zeolites exhibit significant reduction in water decomposition overvoltage as compared to smooth polycrystalline platinum.