NOx release from a noble metal/BaO catalyst: dependence on gas composition

Amberntsson, Annika; Persson, Hans; Engström, Per; Kasemo, Bengt Herbert

doi:10.1016/s0926-3373(00)00266-6

Cited by 86 publications

(35 citation statements)

References 8 publications

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“…During storage at 300°C, the NO x concentration continuously increases until the fuel rich cycle starts, where the NO x concentration increases fast for a short time. This overshooting has been observed before and attributed to formation of large amounts of CO 2 promoting NO x release [14]. Remarkable is here, that the maximal concentration of the NO x overshooting is below that of the NO inlet concentration.…”

Section: Dynamic No Storage-reductionsupporting

confidence: 72%

Flame-Made Pt/K/Al2O3 for NO x Storage–Reduction (NSR) Catalysts

et al. 2009

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High surface area Pt/K/Al 2 O 3 catalysts were prepared with a 2-nozzle flame spray method resulting in Pt clusters on c-Al 2 O 3 and amorphous K storage material as evidenced by Raman spectroscopy. The powders had a high NO x storage capacity and were regenerated fast in a model exhaust gas environment. From 300 to 400°C no excess NO x was detected in the off gas during transition from fuel lean to fuel rich conditions, resulting in a highly effective NO x removal performance. Above 500°C, the NSR activity was lost and not recovered at lower temperatures as K-compounds were partially crystallized on the catalyst.

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Section: Dynamic No Storage-reductionsupporting

confidence: 72%

Flame-Made Pt/K/Al2O3 for NO x Storage–Reduction (NSR) Catalysts

et al. 2009

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“…(i) Destabilization of stored NO x resulting from lower O 2 concentration [30]. (ii) Displacement of nitrates (of alkali-or alkaline-earth metal) by formation of hydroxides or carbonates in the presence of CO 2 [30,31].…”

Section: Hypothesized Reaction Network Involved In Nsr Catalyst Regementioning

confidence: 99%

“…Acidic NO 2 transports to and reacts with the basic alkali-/ alkaline-earth components to form stable surface nitrates. www.elsevier.com/locate/apcata Applied Catalysis A: General 293 (2005) [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] During rich conditions, stored nitrates are decomposed to NO x by interaction with reductant molecules and this process is catalyzed by precious metal. ''Released'' NO x is reduced to N 2 on precious metal sites consuming available reductants.…”

Section: Introductionmentioning

confidence: 99%

Spatially resolved in situ measurements of transient species breakthrough during cyclic, low-temperature regeneration of a monolithic Pt/K/Al2O3 NOx storage-reduction catalyst

Choi

Partridge

Daw

2005

Applied Catalysis A: General

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“…When changing from fuel lean to fuel rich conditions, higher NO x outlet than NO inlet concentrations were detected. This effect, called overshooting, had been observed before [10] and was attributed to CO 2 promoted NO x release [17]. In Ce-BaPt higher NO x overshooting than in PtCe-Ba was observed indicating a higher Pt activity.…”

Section: Catalytic Performancementioning

confidence: 70%

Effect of the Proximity of Pt to Ce or Ba in Pt/Ba/CeO2 Catalysts on NO x Storage–Reduction Performance

et al. 2009

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The effect of Pt location in Pt/Ba/CeO 2 catalysts for NO x storage-reduction (NSR) was analyzed. The Pt location on BaCO 3 or CeO 2 support was controlled by changing the angle (u) between the two flame sprays producing these two components. As-prepared flame-made catalysts contain PtO x which must be reduced during the fuel rich phase to become active for NO x storage and reduction of NO x . For Pt on BaCO 3 this process was significantly faster than for Pt on CeO 2 . The increased reduction ability of Pt on Ba is reflected in the light off temperatures: for Pt on CeO 2 temperatures around 330°C were needed to combust 20% of C 3 H 6 in air while for Pt on BaCO 3 only 250°C were required for the same conversion. The ability to control the location of Pt or other noble metals is, therefore, essential to optimize the catalysts for a given Pt/Ba/CeO 2 weight ratio. The best performance was observed when most of the Pt constituent was located near Ba-containing sites.

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NOx release from a noble metal/BaO catalyst: dependence on gas composition

Cited by 86 publications

References 8 publications

Flame-Made Pt/K/Al2O3 for NO x Storage–Reduction (NSR) Catalysts

Flame-Made Pt/K/Al2O3 for NO x Storage–Reduction (NSR) Catalysts

Spatially resolved in situ measurements of transient species breakthrough during cyclic, low-temperature regeneration of a monolithic Pt/K/Al2O3 NOx storage-reduction catalyst

Effect of the Proximity of Pt to Ce or Ba in Pt/Ba/CeO2 Catalysts on NO x Storage–Reduction Performance

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