Activity in methane combustion and sensitivity to sulfur poisoning of La1−xCexMn1−yCoyO3 perovskite oxides

Alifanti, M.; Auer, Robert; Kirchnerová, J.; Thyrion, F. C.; Grange, Paul; Delmon, Bernard

doi:10.1016/s0926-3373(02)00194-7

Cited by 116 publications

(67 citation statements)

References 32 publications

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“…Our results indicate that neither for dielectric heating nor conventional heating a significant loss in catalytic activity occurs when SO 2 is added at 723 K. Alifanti et al [36] sulphates. Finally, XPS data show a decrease in the Ce 4d peak intensity for the white fraction, indicating that the original Ce oxidic structure has been destroyed, most likely due to the formation of Cerium sulphate.…”

Section: Deactivation By Somentioning

confidence: 54%

Dielectric heating effects on the activity and SO2 resistance of La0.8Ce0.2MnO3 perovskite for methane oxidation

Zhang-Steenwinkel

Castricum

Beckers

et al. 2004

Journal of Catalysis

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Dielectric heating effects on the activity and SO2 resistance of La0.8Ce0.2MnO3 perovskite for methane oxidation Zhang, Y.; Castricum, H.L.; Beckers, J.; Eiser, E.; Bliek, A. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. under dielectric and conventional heating conditions. As these materials are both microwave sensitive and catalytically active, they may be applied as coating material for ceramic soot filters for the reduction of soot emission from Diesel engines. Dielectric heating is shown to result in a much higher CH 4 conversion and a higher resistance to SO 2 poisoning. We propose that local hot spots on the catalytic surface explain the increased activity toward CH 4 conversion. The catalytic activity in SO 2 is largely maintained, as pore blockage by sulphates, as experienced in conventional heating, is counteracted.

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Section: Deactivation By Somentioning

confidence: 54%

Dielectric heating effects on the activity and SO2 resistance of La0.8Ce0.2MnO3 perovskite for methane oxidation

Zhang-Steenwinkel

Castricum

Beckers

et al. 2004

Journal of Catalysis

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“…However, any further investigation to discriminate the nature of the sulphur-containing surface or bulk species forming upon poisoning is beyond the scope of the present work. For this point reference has been made to literature data [1,9,10,12,13] …”

Section: -Results and Discussionmentioning

confidence: 99%

“…form, which promptly react with activated oxygen to form sulphates, sulphites and/or sulphides, depending on temperature and catalyst formulation [5,[9][10][11][12]. The migration of these species from the surface to the bulk has been also observed [1].…”

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confidence: 99%

Effect of sulphur poisoning on perovskite catalysts prepared by flame-pyrolysis

Rossetti

Buchneva

Biffi

et al. 2009

Applied Catalysis B: Environmental

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ABO3 perovskite-like catalysts are known to be sensitive to sulphur-containing compounds. Possible solutions to increase resistance to sulphur are represented by either catalyst bed protection with basic guards or catalyst doping with different transition or noble metals. In the present work La(1-x)A'xCoO3, La(1-x)A'xMnO3 and La(1-x)A'xFeO3, with A' = Ce, Sr and x=0, 0.1, 0.2, either pure or doped with noble metals (0.5 wt% Pt or Pd), were prepared in nano-powder form by flame pyrolysis. All the catalysts were tested for the catalytic flameless combustion of methane, monitoring the activity by on-line mass spectrometry. The catalysts were then progressively deactivated in operando with a new procedure, consisting of repeated injection of some doses of tetrahydrothiophene (THT), usually employed as odorant in the natural gas grid, with continuous analysis of the transient response of the catalyst. The activity tests were then repeated on the poisoned catalyst. Different regenerative treatments were also tried, either in oxidising or reducing atmosphere.Among the unsubstituted samples, higher activity and better resistance to poisoning have been observed in general with manganites with respect to the corresponding formulations containing Co or Fe at the B-site. The worst catalyst showed LaFeO3, from both the points of view of activity and of resistance to sulphur * Corresponding author: fax +39-02-50314300, e-mail ilenia.rossetti@unimi.it 2 poisoning. La0,9Sr0,1MnO3 showed, the best results, exhibiting very high activity and good resistance even after the addition of up to 8.4 mg of THT per g of catalyst.Interesting results were attained also by adding Sr to Co-based perovskites. Sr showed a first action by forcing Mn or Co in their highest oxidation state, but, in addition, it could also act as a sulphur guard, likely forming stable sulphates due to its basicity. Among noble metals, Pt doping proved beneficial in improving the activity of both the fresh and the poisoned catalyst.Keywords: Methane, catalytic combustion; Sulphur poisoning; Perovskite-like catalysts. -INTRODUCTIONThe catalytic flameless combustion (CFC) of methane outperforms conventional flame combustion because of lower emission of pollutants (HC, CO and NOx) and high thermal efficiency. The catalysts traditionally used for CFC are mainly based on supported noble metals, such as Pd and Pt, which ensure high activity, however accompanied by some drawbacks, due to high cost and poor thermal and chemical stability. La-based catalysts with ABO3 perovskite-like structure [1][2][3][4] have been proposed as a valid alternative for the present application. Indeed, perovskite catalysts combine low cost, thermo-chemical stability at high operating temperature and satisfactory catalytic activity [5][6][7][8]. In spite of this, there are still some open questions, especially regarding their resistance to sulphur poisoning when used for the CFC of methane. Indeed, the poisoning mechanism of perovskite-like catalysts has not been completely understood a...

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“…In all of the samples, the La/Co and Ce/Co ratio are both significantly larger than the theoretical ones, suggesting the surface enrichment of A-site elements. This phenomenon was commonly observed for perovskite oxides, and no remarkable connection with their catalytic activities was observed [22]. On the other hand, it is generally accepted that the adsorbed surface oxygen often participates in oxidation reactions.…”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 95%

Catalytic oxidation of nitrogen monoxide over La1−xCexCoO3 perovskites

et al. 2007

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This paper presents an investigation on the NO oxidation properties of perovskite oxides. La 1Àx Ce x CoO 3 (x = 0, 0.05, 0.1, 0.2, 0.3, 0.4) perovskite-type oxides were synthesized through a citrate method and characterized by XRD, BET and XPS. The catalytic activities were enhanced significantly with Ce substitution, and achieved the best when x was 0.2, but decreased at higher x values. The performed characterizations reveal that the adsorbed oxygen on the surface plays an important role in the oxidation of NO into NO 2 . The surface compounds after the co-adsorption of NO and O 2 at room temperature, were investigated by DRIFTS and TPD experiments. Three species: the bridging nitrate, the hyponitrites and the monodentate nitrate, were formed on the surface. The order of thermal stabilities was as follows: monodentate > hyponitrite > bridging. Among them, only the monodentate nitrate which decomposed at above 300 8C, would desorb NO 2 into the gas phase. When Ce was added, the temperature of monodentate nitrate desorption became low and the adsorption of the other two species decreased. This might be related to the oxidation state of Co on the surface. Analysis by synthesizing the characterization results and catalytic activity data shows that large amounts of adsorbed oxygen, small amount of inactive compounds on the surface and low NO 2 desorption temperature are favorable for the oxidation of NO. #

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Activity in methane combustion and sensitivity to sulfur poisoning of La1−xCexMn1−yCoyO3 perovskite oxides

Cited by 116 publications

References 32 publications

Dielectric heating effects on the activity and SO2 resistance of La0.8Ce0.2MnO3 perovskite for methane oxidation

Dielectric heating effects on the activity and SO2 resistance of La0.8Ce0.2MnO3 perovskite for methane oxidation

Effect of sulphur poisoning on perovskite catalysts prepared by flame-pyrolysis

Catalytic oxidation of nitrogen monoxide over La1−xCexCoO3 perovskites

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