Abstract
The reactivity of CeO2, pure or supported on alumina, in NO adsorption and catalytic activity for the CO+NO+O2 reaction (in the absence of metal), has been tested using IR, ESR and temperature-programmed desorption/reactivity techniques. Significant differences are found in alumina-supported ceria in comparison with pure CeO2; its lower activity can be connected to the difficulty of generating on well-dispersed CeO2/Al2O3 the associated oxygen vacancy centers observed on CeO2, which are able to activate reductively NO to give N2O. The same centers might play also a role in enhancing the reduction of surface nitrite species by CO simultaneously with the combustion of the latter molecule.