Experimental results concerning the role of Pt, Rh, Ba, Ce and Al2O3 on NO x -storage catalyst behaviour

Schmeißer, Volker; Perez, J; Tuttlies, Ute; Eigenberger, Gerhart

doi:10.1007/s11244-007-0143-9

Cited by 26 publications

(23 citation statements)

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“…Gas analysis was accomplished with SI-mass spectroscopy (MS 4 ). Further details on the experimental conditions can be found in [7].…”

Section: Methodsmentioning

confidence: 99%

“…In this work we present the further development of the model, based upon detailed kinetic measurements of a Rh/Pt/Ce/Ba/Al 2 O 3 -NSC in a synthetic diesel exhaust gas in the temperature range from 150°C up to 450°C [7]. The work is part of the joint research project "DeNOx-Modell III", where the catalyst samples have kindly been supplied by the commercial catalyst supplier Delphi.…”

Section: Introductionmentioning

confidence: 99%

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Towards a realistic simulation model for NOx-storage catalyst dynamics

2007

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A model of a Pt/Rh/Ce/Ba/Al 2 O 3 -NO x -storage catalyst has been developed. It considers the influence of typical exhaust components on the NO-oxidation and NO x -reduction reactions under realistic flow conditions over a wide temperature range. The NO x -storage dynamics are limited by the diffusion of the reactants into the Ba-particle through an increasingly thick, dense nitrate layer. The regeneration reaction instead is fast since the nitrate shell breaks up. By calculation of the nitrate front position and the nitrate fraction in the Ba-particle, it is possible to describe the complex dynamic behaviour of the NSC.List of symbols a geo geometric washcoat surface (m 2 /m 3 ) a p particle surface (m 2 /m 3 ) a p max maximum particle surface (m 2 /m 3 ) a p min minimum particle surface (m 2 /m 3 ) c p Ba-densitiy of the storage particle (mol/m 3 ) c gas molar density of the gas (mol/m 3 ) D b diffusion coefficient in the gas bulk (m 2 /s) D p st diffusion coefficient in the particle (st.) (m 2 /s) D p reg diffusion coefficient in the particle (reg.) (m 2 /s) E a activation energy (J/mol) I i inhibition term of reaction i (-) k i frequency factor of reaction i (mol/m 3 s) r i reaction rate of reaction i (mol/m 3 s) R molar gas constant (8.314) (J/molAE K) R p storage particle radius (m) t time (s)

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“…Gas analysis was accomplished with SI-mass spectroscopy (MS 4 ). Further details on the experimental conditions can be found in [7].…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Towards a realistic simulation model for NOx-storage catalyst dynamics

2007

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“…However, most of the previous studies focused on the structure characterization or NO x storage capacity testing of the catalyst [12][13][14][15][16][17][18][19], without considering both lean and rich stages of NSR process. As more emphasis has been paid on the reduction process of typical NSR catalyst, we tried to give a realistic evaluation of catalytic behavior for ceria supported catalysts by using different reductants.…”

Section: Introductionmentioning

confidence: 99%

Effects of temperature and reductant type on the process of NOx storage reduction over Pt/Ba/CeO2 catalysts

Wang

2011

Applied Catalysis B: Environmental

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a b s t r a c tThe influences of temperature and reductant type on NO x storage and reduction behavior were studied by transient lean/rich cycles and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments over Pt/Ba/CeO 2 catalysts. It is found that the reducing ability of H 2 is more predominant than that of CO and C 3 H 6 especially at low temperatures. DRIFTS results showed that NO x can be stored as nitrates on both Ba and Ce sites by replacing carbonates species during the lean phase. During the rich phase, however, H 2 regenerated Ba storage sites more effectively than did CO and C 3 H 6 , and Ba(NO 3 ) 2 could be easier reduced than Ce(NO 3 ) 4 . The relatively low reduction performance of CO was attributed to Pt sites being poisoned by CO, which affected low temperature performance, and by carbonates formation, which affected high temperature conversions. The least reactivity of C 3 H 6 was due to its lowest activation ability by the catalysts. Furthermore, water addition had a positive effect on CO reduction ability at 200• C but little influence at elevated temperatures. It was assumed that H 2 O improved the low temperature NO x reduction process by alleviating CO poisoning of Pt.

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“…The NOx storage catalyst (NSC) is one of the most promising concepts for the reduction of NOx from exhaust gas of lean burn combustion engines such as Diesel engines [5,6]. In the NSC, there are precious metals (platinum, rhodium, palladium), various oxides, and other substances useful for NOx storage.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the NOx Storage Catalysts (NSC) Aging: A Preliminary Analytical Study with Electronic Microscopy

et al. 2017

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Featured Application: Could be aided to improve the efficiency of NSC catalysts and thus reduce the environmental impact of thermal-powered vehicles in accordance with the Paris agreement COP21.Abstract: This paper describes an expeditious and reliable method for determining the thermal effects in a static condition of commercial NOx storage catalysts (NSCs) using scanning electron microscopy with an energy dispersive X-ray analytical system (SEM/EDS). It is worth remarking that possible changes in the morphology and in the elemental composition of the catalyst may be considered as the most important causes of the lower conversion of NOx. The information attained in this work indicates that Pt nanoparticle sintering is strongly increased by the oxygen exposure, and this can be considered a very useful preliminary investigation for the studies already present in the literature on the efficiency of NSCs.

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Experimental results concerning the role of Pt, Rh, Ba, Ce and Al2O3 on NO x -storage catalyst behaviour

Cited by 26 publications

References 4 publications

Towards a realistic simulation model for NOx-storage catalyst dynamics

Towards a realistic simulation model for NOx-storage catalyst dynamics

Effects of temperature and reductant type on the process of NOx storage reduction over Pt/Ba/CeO2 catalysts

Evaluating the NOx Storage Catalysts (NSC) Aging: A Preliminary Analytical Study with Electronic Microscopy

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