Reduction of NO by CO over nanoscale LaCo1−xCuxO3 and LaMn1−xCuxO3 perovskites

Zhang, Runduo; Villanueva, Adrian; Alamdari, Houshang; Kaliaguine, Serge

doi:10.1016/j.molcata.2006.05.008

Cited by 101 publications

(49 citation statements)

References 52 publications

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“…3 and 4). The anion vacancies are thought to be the active sites (adsorption sites for O 2 and NO) of perovskite during NO catalytic reduction [7,31,32]. Additionally, abundant molecular oxygen can accelerate nitrate formation which is crucial for C 3 H 6 + NO + O 2 reaction and C 3 H 6 oxidation [9].…”

Section: Role Of Ag Located In Distinct Redox Environmentsmentioning

confidence: 99%

Catalytic Conversion of NO and C3H6 in Exhaust Gases Over Silver Catalysts Under Stoichiometric or Excess Oxygen

2007

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The role of Ag in simultaneously catalyzing NO reduction and C 3 H 6 oxidation was shown to be strongly dependent on the redox properties of its local environment. Under an atmosphere of 1,000 ppm NO, 3,000 ppm C 3 H 6 , and 1% O 2 and a GHSV of 30,000 h -1 , a perovskite La 0.88 Ag 0.12 FeO 3 prepared by reactive grinding is active giving a complete NO conversion and 92% C 3 H 6 conversion at 500°C. These values are much higher than the NO conversion of 55% and C 3 H 6 conversion of 45% obtained over a 3 wt.% Ag/Al 2 O 3 catalyst under the same conditions. Under an excess of oxygen (10% O 2 ) a good SCR performance with a plateau of N 2 yield above 97% over a wide temperature window of 350-500°C along with C 3 H 6 conversion of 90% at 500°C was observed over Ag/ Al 2 O 3 , while minor N 2 yields (~10% at 250-350°C) and high C 3 H 6 conversions (reaching~100% at 450°C) were obtained over La 0.88 Ag 0.12 FeO 3 . Abundant molecular oxygen is desorbed from Ag substituted perovskite after 10% O 2 adsorption as verified by O 2 -temperature programmed desorption (TPD). This reflects the strongly oxidative properties of La 0.88 Ag 0.12 FeO 3 , which lead to a satisfactory NO reduction at 1% O 2 due to the ease of nitrate formation but to a significant C 3 H 6 combustion above that value. The formation of nitrate species over the less oxidizing Ag/Al 2 O 3 was accelerated under an excess of oxygen resulting in an excellent lean NO reduction behavior. The redox properties of silver catalysts could be adjusted via mixing perovskite with alumina for an optimal elimination of both NO and C 3 H 6 over the whole range of oxygen concentration between 0 to 10%.

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Section: Role Of Ag Located In Distinct Redox Environmentsmentioning

confidence: 99%

Catalytic Conversion of NO and C3H6 in Exhaust Gases Over Silver Catalysts Under Stoichiometric or Excess Oxygen

2007

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“…It has been reported that Cu-based catalysts, such as Cu-exchanged zeolites [1], Cucontaining perovskite catalysts [2][3][4], and copper oxides supported on metal oxides [5][6][7] etc., exhibit good catalytic activity for NO abatement reactions. Among them, Cu/CeO 2 and Ce 1-x Cu x O 2 have been received great attention, due to the unique redox behavior of CeO 2 and the special interaction between copper and ceria [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Mg Addition on the Physical and Catalytic Properties of Cu/CeO2 for NO + CO Reduction

Chen

Zhan

et al. 2009

Catal Lett

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Copper catalysts supported on magnesia promoted ceria are synthesized and used for NO reduction by CO. The supports and the subsequent Cu catalysts are prepared by citric acid sol-gel and impregnation methods, respectively. The results of N 2 -physisorption, XRD, EPR and TPR measurements indicate that the Mg addition promotes not only the dispersion of CuO, but also the formation of Cu-O-Ce solid solution. The highest amount of Cu-O-Ce solid solution is found in catalyst modified with 5 wt.% MgO . Based on the catalytic performance, two active sites for the reduction NO by CO are proposed: copper matrix and Cu-O-Ce solid solution. The former does not require the involvement of oxygen vacancy and is more active at low temperature range (T \ 200°C), while the latter shows higher NO conversion at temperature above 200°C, due to the easy regeneration of oxygen vacancy. Also, it is found that the NO conversion over copper matrix is suppressed, while that over Cu-O-Ce solid solution is stimulated in high CO concentration.

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“…2). According to our previous study for the interconversion between NO and CO [22], it was found that the lanthanum cobaltites were able to act as an ''oxygen reservoir'' to capture oxygen atoms via NO dissociation and deliver these oxygens to CO molecule via a subsequent oxidation. The carbon oxidation by NO seems to involve a similar process.…”

Section: Resultsmentioning

confidence: 99%

The Influence of O2, Hydrocarbons, CO, H2, NO x , SO2, and Water Vapor Molecules on Soot Combustion over LaCoO3 Perovskite

et al. 2009

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The effect of various gases (O 2 , hydrocarbons, CO, H 2 , NO x , SO 2 , and H 2 O vapor) presenting in the diesel exhaust on soot combustion using LaCoO 3 as a catalytic material was investigated in this paper. A significant promotion of the combustion rate was found following a trend of 10% H 2 O addition [ 3,000 ppm NO x [ 1% H 2 or 3,000 ppm C 3 H 6 addition, while the improvement in soot oxidation due to the introduction of 3,000 ppm CO or 3,000 ppm CH 4 into the reactant gas is relatively less. The wet pretreatment of LaCoO 3 with 10% steam before soot oxidation hardly affects the combustion behavior. Interestingly, 10% water vapor in the reaction feed produced a significant promoting effect on combustion. In contrast, 30 ppm SO 2 treating led to an obvious deactivation likely owing to the coverage of active sites by sulfate compounds.

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Reduction of NO by CO over nanoscale LaCo1−xCuxO3 and LaMn1−xCuxO3 perovskites

Cited by 101 publications

References 52 publications

Catalytic Conversion of NO and C3H6 in Exhaust Gases Over Silver Catalysts Under Stoichiometric or Excess Oxygen

Catalytic Conversion of NO and C3H6 in Exhaust Gases Over Silver Catalysts Under Stoichiometric or Excess Oxygen

Effect of Mg Addition on the Physical and Catalytic Properties of Cu/CeO2 for NO + CO Reduction

The Influence of O2, Hydrocarbons, CO, H2, NO x , SO2, and Water Vapor Molecules on Soot Combustion over LaCoO3 Perovskite

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