THE ROLE OF OXYGEN VACANCIES ON CERIA SURFACES IN THE OXIDATION OF CARBON-MONOXIDE

Computer simulation techniques are used to model the surfaces of ceria , paying special attention to the effects of surface structures and en ergetics on catalytic activity. Three surfaces of CeO2 have been inves tigated for both their structure and relative stability. The results s how that the three low energy surfaces are the (111), (110) and (310) with the first of these three being the most stable. These surfaces wi ll dominate the morphology of the material. Defects including oxygen v acancies and reduced cerium ions are found to be more stable at the su rfaces than in the bulk of the crystal. Finally, we show that the read y formation of oxygen vacancies on the (110) and (310) surfaces of CeO 2 significantly promotes the oxidation of carbon monoxide.