The effect of C(s) on the trapping of NOx onto Pt/Ba/Al2O3 catalysts

Removal of NOx and soot over Ce/Zr/K/Me (Me = Fe, Pt, Ru, Au) oxide catalysts

“…a lower value if compared to that measured in the absence of soot (6.2 × 10 −4 mol/g cat ). This indicates a negative effect of soot on the NO x storage capacity which could ascribed to the decrease of the NO 2 gas phase concentration [73,74,[10][11][12][13]. In fact, K and soot are expected to compete for reaction with NO 2 leading to the observed decrease in the NO x storage properties, being NO 2 involved in the soot combustion instead of nitrates formation.…”

On the activity and stability of Pt-K/Al2O3 LNT catalysts for diesel soot and NOx abatement

“…the reviews by Epling et al [9] or Roy and Baiker [10] and references therein), investigations on the DPNR system are very scarce. Besides, most of them are focused on the effect of soot on the NO x storage efficiency of LNT systems or on the interaction between the NO x storage function and soot oxidation capacity [8,[11][12][13][14] rather than on the combined soot-NO x reduction activity under lean-rich cycling conditions, typical of the DPNR technology [15].…”

An Overview on the Catalytic Materials Proposed for the Simultaneous Removal of NOx and Soot

“…Similar trends were also reported by Cortés-Reyes et al [89] who observed lower NO x adsorption rate in the presence of soot than in the absence (from 9.5 × 10 −3 to 4.5 × 10 −3 mg min −1 ), while once the catalyst becomes regenerated the adsorption rate of NO x backs to its original values. This negative effect of soot on the NO x storage capacity was explained by a less availability of NO 2 for storage due to its involvement in the soot oxidation, i.e., Ba and soot compete in the reaction with NO 2 [85,90]. On the basis of the so-called "nitrate" route for the storage of NO x (i.e., NO oxidation to NO 2 and subsequent NO 2 adsorption in the form of nitrates via a disproportion reaction [91]), soot was blamed to offer another path for the use of NO 2 rather than the NO x storage process, i.e., being NO 2 involved in the soot oxidation instead of surface NO x formation ( Figure 10).…”