On the mechanism of sulphur poisoning and regeneration of a commercial gasoline NOx-storage catalyst

Rohr, F.; Peter, S.; Lox, E.S.; Kögel, M.; Sassi, Alain; Juste, L.; Rigaudeau, C.; Belot, G.; Gélin, P.; Primet, Michel

doi:10.1016/j.apcatb.2004.09.011

Cited by 89 publications

(67 citation statements)

References 8 publications

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“…However, in order to circumvent some of the unfavorable aspects of pure TiO 2 such as the limited thermal stability, low surface area, and poor mechanical properties, its combination with secondary oxides can be considered to design novel support materials with enhanced properties. Along these lines, γ-Al 2 O 3 25-27 and/or ZrO 2 28-30 are among the promising choices for the secondary oxides that can be used in combination with TiO 2 for improving the sulfur tolerance of the NSR catalysts by suppressing the sulfur adsorption and promoting the sulfur desorption from the surface. It was reported that using a mixture of TiO 2 and γ-Al 2 O 3 as a support material minimized the amount of SO x deposit on a Pt/Ba/γ-Al 2 O 3 catalyst and enhanced the NO x storage of the sulfur-exposed catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…Numerous efforts [3][4][5] have been directed toward designing highly active NSR catalysts with long-term durability and improved sulfur tolerance. Various experimental and theoretical studies [6][7][8][9] also focused on the properties of the Pt/BaO/γ-Al 2 O 3 NSR catalytic system and its application to diesel-fueled vehicles which operate under excess oxygen.…”

Section: Introductionmentioning

confidence: 99%

“…After the complete dilution of the precursor solution with deionized water, γ-Al 2 O 3 (PURAL-OX, 200 m 2 /g, SASOL GmbH, Germany) was slowly added to the aqueous solution under constant stirring at room temperature. Next, the slurry was continuously stirred and 30 vol % NH 3 was slowly added to the solution in order to maintain a condition where pH g 9.0. Gel formation started to be observed after the pH adjustment.…”

Section: Introductionmentioning

confidence: 99%

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Nature of the Ti−Ba Interactions on the BaO/TiO₂/Al₂O₃ NO_x Storage System

et al. 2009

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A ternary oxide-based NO x storage material in the form of BaO/TiO 2 /γ-Al 2 O 3 was synthesized and characterized. Thermally induced structural changes occurring on the surfaces of the TiO 2 /γ-Al 2 O 3 and BaO/ TiO 2 /γ-Al 2 O 3 systems were studied in a comparative manner within 300-1273 K via X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and BET surface area analysis. The surface acidity of the studied oxide systems was also investigated via pyridine adsorption monitored by in-situ Fourier transform infrared (FTIR) spectroscopy. BaO/TiO 2 /γ-Al 2 O 3 ternary oxide was synthesized by incorporating different loadings of (8-20 wt %) BaO onto the TiO 2 /γ-Al 2 O 3 support material, which was originally prepared using the sol-gel method. In the TiO 2 /γ-Al 2 O 3 binary oxide support material, anatase phase exhibited a relatively high thermal stability at T e 1073 K. The presence of TiO 2 domains on the surface of the alumina particles was found to alter the surface acidity of alumina by providing new medium-strength Lewis acid sites. SEM/EDX results indicate that in the BaO/TiO 2 /γ-Al 2 O 3 system, TiO 2 domains present a significant affinity toward BaO and/or Ba(NO 3 ) 2 resulting in a strong Ti-Ba interaction and the formation of overlapping domains on the surface. The presence of TiO 2 also leads to a decrease in the decomposition temperature of the Ba(NO 3 ) 2 phase with respect to the Ti-free Ba(NO 3 ) 2 /γ-Al 2 O 3 system. Such a destabilization is likely to occur due to a weaker interaction between Ba(NO 3 ) 2 and γ-Al 2 O 3 domains in the ternary oxide as well as due to the change in the surface acidity in the presence of TiO 2 . At relatively high temperatures (e.g., 873-1273 K) formation of complex structures in the form of BaTiO 3 , Ba 1.23 Al 2.46 Ti 5.54 O 16 , BaTiO 5 , and/or Ba x Al y Ti z O n were also observed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nature of the Ti−Ba Interactions on the BaO/TiO₂/Al₂O₃ NO_x Storage System

et al. 2009

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“…For a large number of oxide substrates, the stability of some of the common adsorbates increases in the following order: NO 2 − ∼ CO 3 2− < NO 3 − < SO 4 2− [10][11][12][13][14][15]. Thus, sulfur effectively blocks the catalytic sites for NO x storage and gradually reduces the overall NO x storage capacity of the NSR catalysts [16].…”

Section: Introductionmentioning

confidence: 99%

SO uptake and release properties of TiO2/Al2O3 and BaO/TiO2/Al2O3 mixed oxide systems as NO storage materials

et al. 2012

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“…[9][10][11][12] Thus, efforts toward improving the catalytic tolerance against sulfur poisoning and designing highly active and stable novel NSR catalysts are extremely crucial. [13][14][15] One of the areas that have been a major target in numerous studies [16][17][18][19] in the past decade is the development of an optimal support material that will improve the catalytic stability by assisting the formation of sulfur resistant species in the catalytic system.…”

Section: Introductionmentioning

confidence: 99%

Fine-Tuning the Dispersion and the Mobility of BaO Domains on NO_x Storage Materials via TiO₂ Anchoring Sites

2010

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In an attempt to control the surface dispersion and the mobility of BaO domains on NO x storage materials, TiO 2 /TiO x anchoring sites were introduced on/inside the conventional γ-Al 2 O 3 support matrix. BaO/TiO 2 / Al 2 O 3 ternary oxide materials were synthesized via two different sol-gel preparation techniques, with varying surface compositions and morphologies. The synthesized NO x storage materials were studied via XRD, Raman spectroscopy, BET surface area analysis, TPD, XPS, SEM, EDX-mapping, and in situ FTIR spectroscopy of adsorbed NO 2 . NO x uptake properties of the BaO/TiO 2 /Al 2 O 3 materials were found to be strongly influenced by the morphology and the surface structure of the TiO 2 /TiO x domains. An improved Ba surface dispersion was observed for the BaO/TiO 2 /Al 2 O 3 materials synthesized via the coprecipitation of alkoxide precursors, which was found to originate mostly from the increased fraction of accessible TiO 2 /TiO x sites on the surface. These TiO 2 /TiO x sites function as strong anchoring sites for surface BaO domains and can be tailored to enhance surface dispersion of BaO. TPD experiments suggested the presence of at least two different types of NO x species adsorbed on the TiO 2 /TiO x sites, with distinctively different thermal stabilities. The relative stability of the NO x species adsorbed on the BaO/TiO 2 /Al 2 O 3 system was found to increase in the following order: NO + /N 2 O 3 on alumina , nitrates on alumina < surface nitrates on BaO < bridged/bidentate nitrates on large/isolated TiO 2 clusters < bulk nitrates on BaO on alumina surface and bridged/bidentate nitrates on TiO 2 crystallites homogenously distributed on the surface < bulk nitrates on the BaO sites located on the TiO 2 domains.

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On the mechanism of sulphur poisoning and regeneration of a commercial gasoline NOx-storage catalyst

Cited by 89 publications

References 8 publications

Nature of the Ti−Ba Interactions on the BaO/TiO₂/Al₂O₃ NO_x Storage System

Nature of the Ti−Ba Interactions on the BaO/TiO₂/Al₂O₃ NO_x Storage System

SO uptake and release properties of TiO2/Al2O3 and BaO/TiO2/Al2O3 mixed oxide systems as NO storage materials

Fine-Tuning the Dispersion and the Mobility of BaO Domains on NO_x Storage Materials via TiO₂ Anchoring Sites

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On the mechanism of sulphur poisoning and regeneration of a commercial gasoline NOx-storage catalyst

Cited by 89 publications

References 8 publications

Nature of the Ti−Ba Interactions on the BaO/TiO2/Al2O3 NOx Storage System

Nature of the Ti−Ba Interactions on the BaO/TiO2/Al2O3 NOx Storage System

SO uptake and release properties of TiO2/Al2O3 and BaO/TiO2/Al2O3 mixed oxide systems as NO storage materials

Fine-Tuning the Dispersion and the Mobility of BaO Domains on NOx Storage Materials via TiO2 Anchoring Sites

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Nature of the Ti−Ba Interactions on the BaO/TiO₂/Al₂O₃ NO_x Storage System

Nature of the Ti−Ba Interactions on the BaO/TiO₂/Al₂O₃ NO_x Storage System

Fine-Tuning the Dispersion and the Mobility of BaO Domains on NO_x Storage Materials via TiO₂ Anchoring Sites