Influence of Ceria on the NOx Storage/Reduction Behavior of Lean NOx Trap Catalysts

摘要: The effect of La 2 O 3 -stabilized ceria incorporation on the functioning fully formulated lean NO x trap catalysts was investigated. Monolithic were prepared, corresponding to loadings 0, 50 and 100 g CeO /L, together with a catalyst containing g/L ceria-zirconia (Ce 0.7 Zr 0.3 ). Loadings other main components (Pt, Rh BaO) held constant. Catalyst evaluation performed bench flow reactor under simulated diesel exhaust conditions, employing storage/reduction cycles. storage efficiency in temperature range 150-350 °C observed increase loading, resulting higher conversion levels. At 150 °C, high rich phase slip for all catalysts, from an imbalance rates nitrate decomposition reduction. Optimal obtained 250-350 while at 450 most highly loaded ceria-containing resulted lower than ceria-free formulation. N major reduction product over although low levels limited yield. temperatures reduction, NH formation also observed. Selectivity decreased increasing indicating that is consumed by reaction stored oxygen rear catalyst.