PARTICULATE CU ON ORDERED AL2O3 - REACTIONS WITH NITRIC-OXIDE AND CARBON-MONOXIDE

The growth of small Cu particles, prepared by vacuum vapor deposition, on Al2O3 films on Mo(100) has been studied in the 80-800 K substrate temperature range with Anger electron spectroscopy (AES) and temperature-programmed desorption (TPD). A model based on Auger measurements has been utilized to examine the number density and the average size of the Cu particles on Al2O3. Nitric oxide decomposition on the Cu particles has been further investigated using TPD and high-resolution electron energy loss spectroscopy (HREELS). TPD and HREELS data clearly show that a fraction of the NO molecules react with the Cu particles to produce gaseous N-2 and N2O in the 90-250 K temperature range. The formation of N-2 at 770 K is also evident and is due to the recombination of adsorbed N atoms from NO dissociation. The effects of retained oxygen, adsorption temperature, and particle size on the production of high-temperature NT? have been examined. The reaction between nitric oxide and carbon monoxide has also been studied. The results show that, besides the N-2 and N2O products arising from NO decomposition, a small quantity of CO2 is produced by the reaction between adsorbed CO and adsorbed oxygen.