The reduction of NO, by CO was studied over gold catalyst supported on ceria and ceria-lumina. The mixed supports with different CeO2/Al2O3 ratios were prepared by co-precipitation. The catalysts were characterized by means of XRD. TPR, XPS and Raman spectroscopy. The addition of alumina led to a slight enlargement of the gold particles, while the ceria particle size was decreased. Deeper oxygen vacancies formation in the presence of alumina was detected by TPR, XPS and Raman spectroscopy, compared to the pure ceria support. The samples exhibited a high and stable activity and 100% selectivity towards N-2 was reached at 200 degrees C. (c) 2006 Published by Elsevier B.V.