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 energetics on catalytic activity. Three surfaces of CeO2 have been investigated for both their structure and relative stability. The results show that the three low energy surfaces are the (111), (110) and (310) with the first of these three being the most stable. These surfaces will dominate the morphology of the material. Defects including oxygen vacancies and reduced cerium ions are found to be more stable at the surfaces than in the bulk of the crystal. Finally, we show that the ready formation of oxygen vacancies on the (110) and (310) surfaces of CeO2 significantly promotes the oxidation of carbon monoxide.