Technical Paper
The Pt-Ba Interaction in Lean NOx Trap Systems
2005-04-11
2005-01-1085
In a previous systematic investigation on the adsorption of NOx/O2 over Pt/Al2O3, Ba/Al2O3 and Pt-Ba/Al2O3 samples, a novel pathway for NOx storage was proposed that implies the direct uptake of NO in the presence of oxygen in the form of nitrites at Ba sites nearby Pt. In order to better elucidate the role of the Pt-Ba interaction on NOx storage and reduction, in the present study the adsorption of NOx/O2 and their subsequent reduction was further investigated over Pt-Ba/Al2O3 samples having different Ba loadings; a physical mixture Pt/Al2O3+Ba/Al2O3 was also considered for comparison purposes. A kinetic literature model has been adapted to our catalytic system in order to simulate the transient NOx adsorption over a wide range of operating conditions.
