Rare-Earth Oxides of Manganese and Cobalt Rival Platinum for the Treatment of Carbon Monoxide in Auto Exhaust

Voorhoeve, R. J. H.; Remeika, J. P.; Freeland, P. E.; Matthias, B. T.

doi:10.1126/science.177.4046.353

Cited by 258 publications

(87 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Data show that LaMnO3 and LaCoO3 were the most active catalysts, while LaFeO3 was the less performing one, in spite of its higher lowtemperature activity through the suprafacial mechanism ( Fig.1), as previously observed [6,7,[16][17][18].…”

Section: -Effect Of the Nature Of B Metal On Activity And Resistancesupporting

confidence: 58%

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

Rossetti

Buchneva

Biffi

et al. 2009

Applied Catalysis B: Environmental

View full text Add to dashboard Cite

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...

show abstract

Section: -Effect Of the Nature Of B Metal On Activity And Resistancesupporting

confidence: 58%

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

Rossetti

Buchneva

Biffi

et al. 2009

Applied Catalysis B: Environmental

View full text Add to dashboard Cite

show abstract

“…Already, in 1971, LaCoO 3 perovskite-type oxide was proposed as an economic substitute for noble metal-based exhaust after treatment catalysts [6]. Co-, Fe-, Mn-, and Ru-based perovskite-type oxides exhibited promising activity for the oxidation of CO and the reduction of NO x [7][8][9][10][11]. La 0.8 Sr 0.2 CoO 3 was shown to compare well with 1 wt% Pt/Al 2 O 3 for hydrocarbon oxidation [12].…”

Section: Introductionmentioning

confidence: 99%

Structured Perovskite-Based Catalysts and Their Application as Three-Way Catalytic Converters—A Review

et al. 2014

View full text Add to dashboard Cite

Automotive Three-Way Catalysts (TWC) were introduced more than 40 years ago. Despite that, the development of a sustainable TWC still remains a critical research topic owing to the increasingly stringent emission regulations together with the price and scarcity of precious metals. Among other material classes, perovskite-type oxides are known to be valuable alternatives to conventionally used TWC compositions and have demonstrated to be suitable for a wide range of automotive applications, ranging from TWC to Diesel Oxidation Catalysts (DOC), from NO x Storage Reduction catalysts (NSR) to soot combustion catalysts. The interest in these catalysts has been revitalized in the past ten years by the introduction of the concept of catalyst regenerability of perovskite-based TWC, which is in principle well applicable to other catalytic processes as well, and by the possibility to reduce the amounts of critical elements, such as precious metals without seriously lowering the catalytic performance. The aim of this review is to show that perovskite-type oxides have the potential to fulfil the requirements (high activity, stability, and possibility to be included into structured catalysts) for implementation in TWC.

show abstract

“…Meadowcroft first reported the use of perovskite-type oxides as catalysts in 1970 9 for the electrochemical reduction of oxygen. Soon after that, Voorhoeve et al 10 reported the high catalytic activity of perovskite oxides for heterogeneous oxidation. These studies triggered many other works.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of LaNiO3, LaNi(1-x)Fe xO3 andLaNi(1-x)Co xO3 Perovskite Oxides for Catalysis Application

Lima

Assaf

2002

Mat. Res.

View full text Add to dashboard Cite

Mixed metal oxides with perovskite-type structure show a great potential to be used in catalysis, electrocatalysis and electronic ceramics. Perovskites oxides catalysts with the composition LaNiO 3 , LaNi (1-x) Fe x O 3 and LaNi (1-x) Co x O 3 (x = 0.4 and 0.7) have been synthesized by the precipitation method to be used in the methane reforming to produce hydrogen and synthesis gas. The compounds were characterized by X-ray diffraction, thermogravimetric and differential thermal analysis, inductively coupled plasma atomic emission spectroscopy, surface area measurements, energy dispersive X-ray spectrometry coupled to scanning electron microscopy and temperature programmed reduction. The results showed that a suitable combination of the preparation method with calcination variables (time and temperature) could result in oxides with the desired structure and with important properties at the application point of view in heterogeneous catalysis.

show abstract

Rare-Earth Oxides of Manganese and Cobalt Rival Platinum for the Treatment of Carbon Monoxide in Auto Exhaust

Cited by 258 publications

References 3 publications

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

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

Structured Perovskite-Based Catalysts and Their Application as Three-Way Catalytic Converters—A Review

Synthesis and Characterization of LaNiO3, LaNi(1-x)Fe xO3 andLaNi(1-x)Co xO3 Perovskite Oxides for Catalysis Application

Contact Info

Product

Resources

About