Kinetics of the CO+NO Reaction over Bimetallic Platinum–Rhodium on Alumina: Effect of Ceria Incorporation into Noble Metals

Granger, Pascal; Delannoy, Laurent; Lecomte, J.; Dathy, C.; Praliaud, H.; Leclercq, Loı̈c; Leclercq, G.

doi:10.1006/jcat.2002.3519

Cited by 58 publications

(57 citation statements)

References 41 publications

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“…Current catalytic converters provide a high level of emission control by the removal of NO, CO and HC under stoichiometric condition in gasoline engines. The NO-CO reaction plays a prominent role in the catalytic converter, as the exhaust from automobiles contains suffi cient amount of CO. First reported literature (Kobylinski and Taylor, 1974) and as well as the more recent articles (Chambers et al, 2001;Granger et al, 2002) on the NO-CO reaction indicate good activity of Pt group catalysts. (Frank et al, 1997;Sadhankar and Lynch, 1997).…”

Section: Introductionmentioning

confidence: 92%

Bifurcation Analysis on Pt and Ir for the Reduction of NO by CO

2007

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Oscillations and bistability in heterogeneous catalytic reactions are well known. Oxidation of CO by O 2 on a Pt surface is the renowned example in this category. Extensive literature is available for the NO-CO reaction specially related to oscillation and bistability at low pressure conditions on the Pt catalyst surface. Detailed reaction mechanisms have been proposed for the NO-CO reaction on Pt(100), which shows bifurcations, kinetic oscillations, and multiple steady states under ultra high vacuum (10 -6 -10 -7 bar) conditions due to complex surface dynamics (Fink et al., 1992;Makeeva and Kevrekidis, 2004). It was found that oscillations are observed when C NO /C CO is greater than one and in the temperature range of 100-250ºCDue to the importance of the NO-CO reaction in current catalytic converters, reduction of NO by CO on Pt group catalysts is important to study. Various reaction mechanisms have been proposed for the NO-CO reaction on Pt(100), which shows bifurcations, kinetic oscillations and multiple steady states under ultra high vacuum (UHV) conditions due to complex surface dynamics. Some experiments on supported Pt group catalysts reported in literature show oscillations and bistability under atmospheric conditions as well. Industrially relevant conditions require the modelling and detailed analysis of the system at atmospheric pressure. We have proposed a reaction mechanism for the NO-CO system on Pt group catalysts and coupled it with an isothermal PSR model to obtain solutions at atmospheric conditions with the continuation software CONTENT 1.5, at different operating conditions. Simulation results suggest that Pt(111) shows bifurcations at certain operating conditions while Ir(111) shows stable solutions at all the operating conditions studied here.En raison de l'importance de la réaction entre NO et CO dans les convertisseurs catalytiques habituels, il est important d'étudier la réduction de NO par le CO sur des catalyseurs du groupe Pt. Divers mécanismes de réaction ont été proposés pour la réaction de NO-CO sur Pt(100), qui montre des bifurcations, des oscillations cinétiques et de multiples états permanents dans des conditions de vide extrême en raison de la dynamique de surface complexe. Certaines expériences dans la littérature scientifi que sur des catalyseurs de groupe Pt supportés montrent en outre des oscillations et une bi-stabilité dans des conditions atmosphériques. Des conditions industrielles pertinentes requièrent la modélisation et l'analyse détaillée du système à la pression atmosphérique. On a proposé un mécanisme de réaction pour le système de NO-CO sur des catalyseurs de groupe Pt et on l'a couplé avec un modèle PSR isotherme afi n d'obtenir des solutions dans des conditions atmosphériques avec le logiciel de continuation CONTENT 1.5, dans différentes conditions opératoires. Les résultats des simulations suggèrent que Pt(111) montre des bifurcations à certaines conditions opératoires, tandis que l'Ir(111) montre des solutions stables à toutes les conditions opératoires étudié...

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Section: Introductionmentioning

confidence: 92%

Bifurcation Analysis on Pt and Ir for the Reduction of NO by CO

2007

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“…Silva and Schmal [14] show that the -NCO species is an important intermediate in the NO reduction by CO while Granger et al [6] suggest that the formation of N 2 directly from NO dissociation might be the important step for NO reduction. The literature experimental results show that N 2 O is formed as an undesired product during the NO-CO reaction on Pt group catalysts [4].…”

Section: Elementary Reaction Mechanism and Reactor Modelmentioning

confidence: 99%

“…The literature experimental results show that N 2 O is formed as an undesired product during the NO-CO reaction on Pt group catalysts [4]. Some articles indicate that N 2 O is an intermediate in the formation of N 2 [5,6]. However, the formation of N 2 O is not considered in many of the quantitative detailed surface reaction mechanisms proposed in literature (Oh et al [15] on Rh (1 1 1) and Rh/Al 2 O 3 catalysts, Makeeva and Kevrekidis [16] on Pt (1 0 0), Sarkar and Khanra [17] on Pt-Rh and Pd-Rh, and so on).…”

Section: Elementary Reaction Mechanism and Reactor Modelmentioning

confidence: 99%

“…The detailed analysis of the NO-CO system on Pt catalyst using the CSTR model is given elsewhere [27]. The available articles in the literature [5,6,12] on models for the NO-CO reaction are based on global reaction kinetics considering rate limiting step(s), and involve extensive parameter fitting. We propose here a microkinetic model involving no rate limiting step assumptions or parameter fitting, and obtain good quantitative match with literature experimental data over the full range of measured temperatures.…”

Section: Pbr/cstr Modelmentioning

confidence: 99%

“…Selective catalytic reduction using hydrocarbons (HC-SCR) is found to be effective for NO x control [1][2][3]. The reactions between CO and NO are important in HC-SCR and CO is found to be a good reducing agent for NO x [4][5][6][7]. The use of CO as a reducing agent has advantages for practical application because of its presence in significant amounts in automobile exhausts.…”

Section: Introductionmentioning

confidence: 99%

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NO Reduction Over Noble Metal Ionic Catalysts

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2011

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In last 40 years, catalysis for NO x removal from exhaust gas has received much attention to achieve pollution free environment. CeO 2 has been found to play a major role in the area of exhaust catalysis due to its unique redox properties. In last several years, we have been exploring an entirely new approach of dispersing noble metal ions in CeO 2 and TiO 2 for redox catalysis. We have extensively studiedPt, Rh, Ru) catalysts for exhaust catalysis especially NO reduction and CO oxidation, structure-property relation and mechanism of catalytic reactions. In these catalysts, lower valent noble metal ion substitution in CeO 2 and TiO 2 creates noble metal ionic sites and oxide ion vacancy. NO gets molecularly adsorbed on noble metal ion site and dissociatively adsorbed on oxide ion vacancy site. Dissociative chemisorption of NO on oxide ion vacancy leads to preferential conversion of NO to N 2 instead of N 2 O over these catalysts. It has been demonstrated that these new generation noble metal ionic catalysts (NMIC) are much more catalytically active than conventional nano crystalline noble metal catalysts especially for NO reduction.

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Kinetics of the CO+NO Reaction over Bimetallic Platinum–Rhodium on Alumina: Effect of Ceria Incorporation into Noble Metals

Cited by 58 publications

References 41 publications

Bifurcation Analysis on Pt and Ir for the Reduction of NO by CO

Bifurcation Analysis on Pt and Ir for the Reduction of NO by CO

Detailed surface reaction mechanism for reduction of NO by CO

NO Reduction Over Noble Metal Ionic Catalysts

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