Behavior of Active Oxygen During the Decomposition of Nitrous Oxide Over Fe-FER

Nováková, J.; Sobalı́k, Zdenĕk

doi:10.1007/s10562-009-9958-2

Cited by 5 publications

(1 citation statement)

References 14 publications

(19 reference statements)

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“…Metal-exchanged zeolites (ZSM-5, MOR, BEA, and FER), especially the Fe−ZSM-5 system, have received widespread attention because of their high catalytic activity in many chemical processes, including the selective catalytic reduction (SCR) of NO x with ammonia or hydrocarbons, − the decomposition − or catalytic reduction of N 2 O, the oxidative dehydrogenation of propane, and the oxidation of benzene, biphenyl, and benzonitrile. − Upon analysis of the application of metal-exchanged zeolites in the SCR process aboard diesel vehicles, one challenge is to achieve high activity and selectivity over a broad range of temperatures from about 200 to 700 °C. However, iron-exchanged zeolites are only long-term stable under hydrothermal conditions to about 500 °C.…”

Section: Introductionmentioning

confidence: 99%

Effect of Structural and Preparation Parameters on the Activity and Hydrothermal Stability of Metal-Exchanged ZSM-5 in the Selective Catalytic Reduction of NO by NH₃

Brandenberger

Kröcher

Tißler³

et al. 2011

Ind. Eng. Chem. Res.

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The influence of the nature of metal ion, framework type, exchange method and exchange degree, the addition of NO 2 to the gas flow and the introduction of Al, Nb, and Mn on the selective catalytic reduction (SCR) of NO x with ammonia over ZSM-5 and BEA catalysts was studied before and after hydrothermal aging. From the results, it was concluded that the stability of metal-exchanged zeolites is governed by the framework type, among which Fe-BEA showed superior hydrothermal stability, Cu-ZSM-5 and Fe-ZSM-5 showed medium hydrothermal stability, and Cu-BEA showed relatively low hydrothermal stability. The choice of the exchange metal was a key factor for the activity of the zeolite, whereas Cu showed high low-temperature activity and Fe showed high high-temperature activity in the SCR reaction. Simultaneously exchanged Fe/Cu-ZSM-5 combined the advantages of both exchange metals in one catalyst. The Si/Al ratio did not directly influence the activity or stability. The initial activity was not influenced by the exchange method, but with respect to stability, the chemical vapor ion-exchange method was clearly favored. However, in view of ease of catalyst preparation, liquid phase ion exchange and solid state ion exchange are the preferred methods. By feeding an NO/NO 2 = 1:1 mixture, the SCR activity is increased by a factor of about 10-30 for fresh Fe-ZSM-5 W (0.3) and about 30-100 for aged Fe-ZSM-5 W (0.3) compared to only NO. The introduction of extraframework Al in ZSM-5 zeolites and the use of an Fe 3þ metal salt as a precursor improved the stability of the Fe-ZSM-5 zeolites against hydrothermal aging in terms of the SCR activity. On the other hand, neither the introduction of Nb or La nor the simultaneous exchange of Mn and Fe enhanced the NO conversion after aging.

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Section: Introductionmentioning

confidence: 99%

Effect of Structural and Preparation Parameters on the Activity and Hydrothermal Stability of Metal-Exchanged ZSM-5 in the Selective Catalytic Reduction of NO by NH₃

Brandenberger

Kröcher

Tißler³

et al. 2011

Ind. Eng. Chem. Res.

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Mechanism of Framework Oxygen Exchange in Fe‐Zeolites: A Combined DFT and Mass Spectrometry Study

et al. 2013

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The role of framework oxygen atoms in N(2)O decomposition [N(2)O(g)→N(2)(g) and 1/2O(2)(g)] over Fe-ferrierite is investigated employing a combined experimental (N(2)(18)O decomposition in batch experiments followed by mass spectroscopy measurements) and theoretical (density functional theory calculations) approach. The occurrence of the isotope exchange indicates that framework oxygen atoms are involved in the N(2)O decomposition catalyzed by Fe-ferrierite. Our study, using an Fe-ferrierite sample with iron exclusively present as Fe(II) cations accommodated in the cationic sites, shows that the mobility of framework oxygen atoms in the temperature range: 553 to 593 K is limited to the four framework oxygen atoms of the two AlO(4)(-) tetrahedra forming cationic sites that accomodate Fe(II). They exchange with the Fe extra-framework (18)O atom originating from the decomposed N(2)(18)O. We found, using DFT calculations, that O(2) molecules facilitate the oxygen exchange. However, the corresponding calculated energy barrier of 87 kcal mol(-1) is still very high and it is higher than the assumed experimental value based on the occurrence of the sluggish oxygen exchange at 553 K.

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Role of active oxygen and NOx species in N2O decomposition over Fe-ferrierite

Sobalı́k

Tábor

Nováková

et al. 2012

Journal of Catalysis

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Behavior of Active Oxygen During the Decomposition of Nitrous Oxide Over Fe-FER

Cited by 5 publications

References 14 publications

Effect of Structural and Preparation Parameters on the Activity and Hydrothermal Stability of Metal-Exchanged ZSM-5 in the Selective Catalytic Reduction of NO by NH₃

Effect of Structural and Preparation Parameters on the Activity and Hydrothermal Stability of Metal-Exchanged ZSM-5 in the Selective Catalytic Reduction of NO by NH₃

Mechanism of Framework Oxygen Exchange in Fe‐Zeolites: A Combined DFT and Mass Spectrometry Study

Role of active oxygen and NOx species in N2O decomposition over Fe-ferrierite

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Behavior of Active Oxygen During the Decomposition of Nitrous Oxide Over Fe-FER

Cited by 5 publications

References 14 publications

Effect of Structural and Preparation Parameters on the Activity and Hydrothermal Stability of Metal-Exchanged ZSM-5 in the Selective Catalytic Reduction of NO by NH3

Effect of Structural and Preparation Parameters on the Activity and Hydrothermal Stability of Metal-Exchanged ZSM-5 in the Selective Catalytic Reduction of NO by NH3

Mechanism of Framework Oxygen Exchange in Fe‐Zeolites: A Combined DFT and Mass Spectrometry Study

Role of active oxygen and NOx species in N2O decomposition over Fe-ferrierite

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Effect of Structural and Preparation Parameters on the Activity and Hydrothermal Stability of Metal-Exchanged ZSM-5 in the Selective Catalytic Reduction of NO by NH₃

Effect of Structural and Preparation Parameters on the Activity and Hydrothermal Stability of Metal-Exchanged ZSM-5 in the Selective Catalytic Reduction of NO by NH₃