Surface reactivity of prereduced rare earth oxides with nitric oxide: New approach for NO decomposition

Abstract

Direct decomposition of NO to N₂ by rare earth oxides prereduced with H₂ was studied. CeO₂ and Pr₆O₁₁ prereduced at 773 K, in which many oxygen anion vacancies exist, decomposed NO to N₂ at 673 K. The addition of Pt accelerated the dissociation of NO to N₂. The amount of NO decomposed to N₂ and N₂O by Pt supported on rare earth oxides was strongly related to the oxygen mobility and to the amount of oxygen anion vacancies in the surface/subsurface. Particularly, for Pt/CeO₂, oxygen diffusion on the surface but not in the bulk was the most important factor determining the NO decomposition activity.