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Rodrigues, Fábio M. S.; Juste, L.; Potvin, Claude; Tempere, J. F.; Blanchard, G.; Djéga‐Mariadassou, Gérald

doi:10.1023/a:1009001630673

Cited by 100 publications

(43 citation statements)

References 11 publications

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“…In fact, through analysis of sequential evolution of H 2 O and CO 2 Lietti et al [24] and Nova et al [25] have reported that at 360 • C BaO, Ba(OH) 2 and BaCO 3 coexist on a fresh sample and the NO x is stored on BaO first, then on Ba(OH) 2 and finally on BaCO 3 . The order of displacement of these species by NO x , when CO 2 and H 2 O were absent from the feed, also falls in line with the thermodynamic predictions of Rodrigues et al [17] and Kobayashi et al [26]. Thus, it is known that the chemical state of Ba at the beginning of the NO x exposure affects the kinetics of displacement of the respective surface species by NO x , which in turn affects the fast NSC of the traps.…”

Section: Introductionsupporting

confidence: 84%

“…Any discussion about the application of these LNTs to realistic cases is not complete without inclusion of CO 2 and H 2 O, which are invariably present in the exhaust of lean burn engines. It is well known that CO 2 and H 2 O result in the presence of carbonate and hydroxide species on Ba which are detrimental to the NO x storage capacity of the traps due to morphological changes in the Ba phase caused by H 2 O and the thermodynamic stability of the surface species resulting in slower NO x adsorption kinetics [1,[10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Many of these studies were performed on samples with various Pt and Ba loadings, at different CO 2 and H 2 O concentrations in the lean feed with various lean-rich cycling protocols, and at a range of operating temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Formation and removal of Ba-carbonates or carboxylates on Pt/BaO/γ-Al2O3 lean NOx traps

Chaugule¹,

Kispersky²,

Ratts³

et al. 2011

Applied Catalysis B: Environmental

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Section: Introductionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Formation and removal of Ba-carbonates or carboxylates on Pt/BaO/γ-Al2O3 lean NOx traps

Chaugule¹,

Kispersky²,

Ratts³

et al. 2011

Applied Catalysis B: Environmental

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“…O 2 \NO 2 . Similar findings were also observed over a commercial NSR catalyst at 400°C [24]. These results indicate that it must be more than just NO oxidation efficiency that dictates performance, otherwise there would be a consistently decreasing difference as the temperature is increased.…”

Section: Introductionsupporting

confidence: 77%

Investigating the Effect of NO Versus NO2 on the Performance of a Model NO X Storage/Reduction Catalyst

Al‐Harbi

Epling

2009

Catal Lett

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The effects of using NO or NO 2 as the NO X source on the performance of a NO X storage/reduction catalyst were investigated from 200 to 500°C. The evaluation included comparison with constant cycling times and trapping the same amount of NO X during the lean phase. With NO 2 as the NO X source, better trapping and reduction performance was attained in comparison to NO, at all operating temperatures except 300°C. This exception, under the conditions tested, was likely due to high NO oxidation activity and rapid trapping of NO 2 , although it is expected that extending the trapping time would lead to consistent differences. Several reasons for the observed improvements at 200, 400 and 500°C with NO 2 relative to NO are discussed. One that can explain the data, for both trapping and release improvement, is treating the monolith as an integral reactor. With NO 2 , more NO X is trapped at the very inlet of the catalyst, whereas with NO, the maximum in trapping during cycling occurs slightly downstream. Thus more of the catalyst can be used for trapping with NO 2 as the NO X source. The decreased release during catalyst regeneration is similarly explained; with more being released at the very inlet, there is more residence time and therefore contact with downstream Pt sites, but more importantly more interaction between reductant and stored NO X . NH 3 and N 2 O measurements support this conclusion.

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“…Lorimer et al [42] have reported a negative order dependence of the NO reduction with CO on Pt/SiO 2 catalyst. The competitive adsorption of CO 2 and NO 2 during the NSR catalysis has been suggested previously [43]. During the reduction by CO or C 3 H 6 , it is likely that some carbonates form on the catalyst surface.…”

Section: No/co Reaction Systemmentioning

confidence: 54%

Micro-kinetics of NO storage and reduction with H2/CO/C3H6 on Pt/BaO/Al2O3 monolith catalysts

Kota

Luss

Balakotaiah

2015

Chemical Engineering Journal

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h i g h l i g h t sMicro-kinetic model for NO x reduction with H 2 , CO, C 3 H 6 is developed. Model includes key intermediates determined in the experiments. Model predicts the steady state conversions for NO, H 2 , CO, C 3 H 6 against temperature. Impact of washcoat diffusion and its effect on kinetic parameters is discussed. g r a p h i c a l a b s t r a c t NO and CO conversion vs inlet CO concentration at 270°C on Pt/Ba/Al 2 O 3 catalyst. a b s t r a c tIsothermal steady state NO x storage and reduction on Pt/BaO/Al 2 O 3 by H 2 /CO/C 3 H 6 reactant mixtures is studied using, 1 + 1 dimensional two-phase model that accounts for washcoat diffusional limitations. It predicts the storage and reduction performance over a wide range of inlet feed concentrations and temperatures. A major limitation of global kinetic models is not being able to predict accurately the performance of the catalyst with changing feed composition. Micro-kinetic models elucidating the role of individual reductants can account for such variations. The temperature dependence of the rate constants has been quantified so that the surface chemistry is consistent with experimental observations. Inclusion of washcoat diffusion enables the model to accurately predict the NO x conversion and zscale-up performance of the catalyst over a wide temperature range. The sensitivity of the estimated kinetic parameters to the effective diffusivities in the washcoat is analyzed. Results indicate that the estimated micro-kinetic parameters are influenced by the washcoat pore structure as well as the properties of the catalytic and storage components.

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Cited by 100 publications

References 11 publications

Formation and removal of Ba-carbonates or carboxylates on Pt/BaO/γ-Al2O3 lean NOx traps

Formation and removal of Ba-carbonates or carboxylates on Pt/BaO/γ-Al2O3 lean NOx traps

Investigating the Effect of NO Versus NO2 on the Performance of a Model NO X Storage/Reduction Catalyst

Micro-kinetics of NO storage and reduction with H2/CO/C3H6 on Pt/BaO/Al2O3 monolith catalysts

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