Sulfur deactivation of Pt/SiO2, Pt/BaO/Al2O3, and BaO/Al2O3 NOx storage catalysts: Influence of SO2 exposure conditions

Dawody, Jazaer; Skoglundh, Magnus; Olsson, Louise; Fridell, Erik

doi:10.1016/j.jcat.2005.05.017

Cited by 48 publications

(35 citation statements)

References 41 publications

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“…The addition of SO 2 to the inlet gas entirely inhibits the NO oxidation to NO 2 observed in the first step of the experiment. In this sense, Dawody et al also reported a negative impact of SO 2 in NO oxidation by platinum in Pt/SiO 2 catalyst [46]. NO concentration in the outlet gas surpasses that of the inlet value when SO 2 was present, which could be related to unreacted NO molecules getting displaced from the adsorption sites by SO 2 .…”

Section: Ssit-ptmentioning

confidence: 97%

“…It is also interesting to observe that, after SO 2 has been removed from the feed stream, the catalyst activity for NO reduction is restored. Pt-loaded silica catalysts generally show high resistance to SO 2 poisoning for NO-SCR [44,46]. Neither sulfur species nor SO 2 evolution was detected by XPS or in the outlet gas during subsequent TPD after reaction, neglecting the possibility of SO 2 chemisorption or interaction with the adsorbed hydrocarbon.…”

Section: Ssit-ptmentioning

confidence: 99%

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Electrospinning of silica sub-microtubes mats with platinum nanoparticles for NO catalytic reduction

Ruiz-Rosas¹,

Rosas²,

Loscertales³

et al. 2014

Applied Catalysis B: Environmental

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Silica sub-microtubes loaded with platinum nanoparticles have been prepared in flexible non-woven mats using co-axial electrosppining technique. A partially gelated sol made from tetraethyl orthosilicate was used as the silica precursor, and oil was used as the sacrificial template for the hollow channel generation. Platinum has been supported on the wall of the tubes just adding the metallic precursor to the sol-gel, thus obtaining the supported catalyst by one-pot method. The silica tubes have a high aspect ratio with external/internal diameters of 400/200 nm and well-dispersed platinum nanoparticles of around 2 nm. This catalyst showed a high NO conversion with very high selectivity to N 2 at mild conditions in the presence of excess oxygen when using C 3 H 6 as reducing agent. This relevant result reveals the potential of this technique to produce nanostructured catalysts onto easy to handle conformations.Keywords: coaxial electrospinning, silica nanotubes, platinum nanoparticles, NOx SCR. Graphical AbstractHighlights  Non-woven mats of platinum-loaded silica nanotubes were obtained by co-axial electrospinning in one-pot procedure. By this technique, high dispersed Pt nanoparticles can be easily deposited on the walls of the silica nanotubes. Pt-loaded silica nanotube non-woven mats show high activity for low temperature NOx SCR with propylene in the presence of excess oxygen and outstanding N 2 selectivity, at the studied operation conditions.

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Section: Ssit-ptmentioning

confidence: 97%

Section: Ssit-ptmentioning

confidence: 99%

Electrospinning of silica sub-microtubes mats with platinum nanoparticles for NO catalytic reduction

Ruiz-Rosas¹,

Rosas²,

Loscertales³

et al. 2014

Applied Catalysis B: Environmental

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“…It is commonly accepted that SO 2 undergoes oxidation to SO 3 over precious metal sites. Experiments over a Pt/Ba/Al 2 O 3 catalyst confirm that SO 2 + O 2 exposure results in the formation of SO 3 that is being trapped as sulfate according the proposed reaction scheme [10].…”

Section: Introductionmentioning

confidence: 71%

“…Formation of bulk BaSO 4 however requires a SO 3 molecule to penetrate into the crystal structure. The activation energy proposed by Dawody et al [10] (1 kJÁmol À1 ) seems fairly low for passing a barrier for breaking bulk Ba-O bonds inside the crystal structure. Instead, we propose a value of 80.5 kJÁmol À1 , that is approximately 1/6 of the atomization energy of crystal BaO [43].…”

Section: Kinetic Studymentioning

confidence: 82%

Sulfur Deactivation of NO_xStorage Catalysts: A Multiscale Modeling Approach

Rankovic

Chizallet

Nicolle

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Re´sume´-Empoisonnement des mate´riaux de stockage des NO x par le soufre : approche multi-e´chelles -Les pie`ges a`NO x repre´sentent une technologie prometteuse pour la re´duction des e´missions d'oxydes d'azote issus des moteurs ope´rant en me´lange pauvre. Leur utilisation est limite´e par la pre´sence de compose´s soufre´s dans les gaz d'e´chappement. Le soufre contenu dans le carburant et le lubrifiant est oxyde´lors de la combustion en SO 2 et SO 3 . Ces oxydes de soufre pre´sentent une forte affinite´pour le mate´riau de stockage du pie`ge, la formation de sulfate e´tant favorise´e thermodynamiquement. Cette formation contribue au blocage des sites d'adsorption des NO x et influence l'ope´ration de l'organe de post-traitement. La mode´lisation mole´culaire repre´sente un outil pre´cieux pour pre´dire le comportement et les performances du syste`me catalytique. Notre e´tude pre´sente une me´thodologie d'exploitation des calculs ab initio pour la formulation de mode`les cine´tiques de´veloppe´s dans la librairie de post-traitement ve´hicule IFP Exhaust. Nous illustrons notre approche par le cas de l'adsorption de SO 3 sur un mate´riau mode`le, BaO. Afin d'obtenir une description fide`le du mate´riau de stockage re´el, l'adsorption de SO 3 est de´crite sur plusieurs sites : terrasses, marches, crans et le site massique. Des analyses de sensibilite´et de vitesses de re´actions permettent d'obtenir une compre´hension plus approfondie des phe´nome`nes d'empoisonnement mis en jeu.Abstract -Sulfur Deactivation of NO x Storage Catalysts: A Multiscale Modeling ApproachLean NO x Trap (LNT) catalysts, a promising solution for reducing the noxious nitrogen oxide emissions from the lean burn and Diesel engines, are technologically limited by the presence of sulfur in the exhaust gas stream. Sulfur stemming from both fuels and lubricating oils is oxidized during the combustion event and mainly exists as SO x (SO 2 and SO 3 ) in the exhaust. Sulfur oxides interact strongly with the NO x trapping material of a LNT to form thermodynamically favored sulfate species, consequently leading to the blockage of NO x sorption sites and altering the catalyst operation. Molecular and kinetic modeling represent a valuable tool for predicting system behavior and evaluating catalytic performances. The present paper demonstrates how fundamental ab initio calculations can be used as a valuable source for designing kinetic models developed in the IFP Exhaust library, intended for vehicle simulations. The concrete example we chose to illustrate our

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“…While the importance of LNT sulfation has long been recognized, and extensive experimental studies have been conducted (Choi et al, 2007;Choi et al, 2008;Choi et al, 2010;Corbos et al, 2008;Dawody et al, 2005;Elbouazzaoui et al, 2005;Engstrom et al, 1999;Happel et al, 2010;Kim et al, 2006;Luo et al, 2008;Sakamoto et al, 2006;Sedlmair et al, 2002;Toops and Pihl, 2008;Wu et al, 2005), very few detailed modeling efforts have been undertaken. Han et al (2005) constructed a complex reactor model for desulfation but chose to focus on the heat generation needed to drive the process, so their chemistry involved only reformate combustion rather than reactions describing the desulfation itself.…”

Section: Introductionmentioning

confidence: 99%

Microkinetic Modeling of Lean NO<sub>x</sub> Trap Sulfation and Desulfation

Larson

2011

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A microkinetic reaction sub-mechanism designed to account for the sulfation and desulfation of a commercial lean NO x trap (LNT) is presented. This set of reactions is appended to a previously developed mechanism for the normal storage and regeneration processes in an LNT in order to provide a comprehensive modeling tool. The reactions describing the storage, release, and reduction of sulfur oxides are patterned after those involving NO x , but the number of reactions is kept to the minimum necessary to give an adequate simulation of the experimental observations. Values for the kinetic constants are estimated by fitting semi-quantitatively the somewhat limited experimental data, using a transient plug flow reactor code to model the processes occurring in a single monolith channel. Rigorous thermodynamic constraints are imposed in order to ensure that the overall mechanism is consistent both internally and with the known properties of all gas-phase species. The final mechanism is shown to be capable of reproducing the principal aspects of sulfation/desulfation behavior, most notably (a) the essentially complete trapping of SO 2 during normal cycling; (b) the preferential sulfation of NO x storage sites over oxygen storage sites and the consequent plug-like and diffuse sulfation profiles; (c) the degradation of NO x storage and reduction (NSR) capability with increasing sulfation level; and (d) the mix of H 2 S and SO 2 evolved during desulfation by temperature-programmed reduction. 4 ACKNOWLEDGMENTS

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Sulfur deactivation of Pt/SiO2, Pt/BaO/Al2O3, and BaO/Al2O3 NOx storage catalysts: Influence of SO2 exposure conditions

Cited by 48 publications

References 41 publications

Electrospinning of silica sub-microtubes mats with platinum nanoparticles for NO catalytic reduction

Electrospinning of silica sub-microtubes mats with platinum nanoparticles for NO catalytic reduction

Sulfur Deactivation of NO_xStorage Catalysts: A Multiscale Modeling Approach

Microkinetic Modeling of Lean NO<sub>x</sub> Trap Sulfation and Desulfation

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Sulfur deactivation of Pt/SiO2, Pt/BaO/Al2O3, and BaO/Al2O3 NOx storage catalysts: Influence of SO2 exposure conditions

Cited by 48 publications

References 41 publications

Electrospinning of silica sub-microtubes mats with platinum nanoparticles for NO catalytic reduction

Electrospinning of silica sub-microtubes mats with platinum nanoparticles for NO catalytic reduction

Sulfur Deactivation of NOxStorage Catalysts: A Multiscale Modeling Approach

Microkinetic Modeling of Lean NO<sub>x</sub> Trap Sulfation and Desulfation

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Sulfur Deactivation of NO_xStorage Catalysts: A Multiscale Modeling Approach