Reaction Mechanism Study of the Di-Air System and Selectivity and Reactivity of NO Reduction in Excess O2

Abstract

We studied the mechanism of NO reduction as well as its selectivity and reactivity in the presence of excess O 2 . Results show that fuel injection and/or pretreatment are important for ceria catalyst reduction and carbon deposition on the catalyst surface. Oxygen defects of reduced ceria are the key sites for the reduction of NO into N 2 . The deposited carbon acts as a buffer reductant, i.e., the oxidation of carbon by lattice oxygen recreates oxygen defects to extend the NO reduction time interval. A small amount of NO showed a full conversion into only N 2 both on the reduced Zr-La doped ceria and reduced Pt-Zr-La doped ceria. Only when the catalyst is oxidised NO is converted into NO 2 .