Selective catalytic reduction of NO by ammonia over Raney-Ni supported Cu-ZSM-5

Ma, Aiyuan; Grünert, Wolfgang

doi:10.1016/s0926-3373(00)00133-8

Cited by 18 publications

(8 citation statements)

References 22 publications

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“…Consequently the basic reaction on SCR catalysts is − 4 NH 3 + 4 NO + O 2 → 4 normalN 2 + 6 H 2 O However, the reaction of a 1:1 mixture of NO and NO 2 is faster than reaction on all materials known today: − 4 NH 3 + 2 NO + 2 NO 2 → 4 normalN 2 + 6 H 2 O In gas feeds with higher NO:NO 2 ratios, the rate-determining step for iron-exchanged zeolites is the oxidation of part of the NO to NO 2 . ,,− Therefore, it is reasonable to conclude that reaction is best at describing the actual general SCR reaction on zeolites and that the NO 2 has to be provided by the gas feed or be produced by the catalyst itself through the oxidation of NO. , As a consequence, the oxidizing potential of the metal ion is one of the main factors that controls the SCR activity of metal-exchanged zeolites for NO:NO 2 feed gas ratios larger than 1. Many different metal ions (e.g., Fe, Cu, Cr, Co, Ni, Mn, Ag, La, Mg, Zn, La, and Ce) have been exchanged in zeolites and pillared clays, of which Fe, Cu, and Cr have proven to be the most active for NH 3 -SCR. ,,,,− …”

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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“…been claimed to be more active than a vanadium reference catalyst for NH 3 -SCR 143 . However, one very critical disadvantage is found for the copper-containing zeolites -they show limited hydrothermal stability 144 . This means that water will poison the catalyst fast.…”

Section: Zeolites As Catalystsmentioning

confidence: 99%

“…A few examples of these iron systems should be mentioned. Catalysts prepared by sublimation of iron(III) chloride on the zeolites are found to exhibit high activity and stability in broad temperature interval 144 . Other catalysts have been prepared by introducing the iron via ion exchange and these catalysts has been claimed to be even better than a V 2 O 5 -WO 3 /TiO 2 reference 146 .…”

Section: Iron-containing Zeolitesmentioning

confidence: 99%

Design of Heterogeneous Catalysts

Ozkan¹

2009

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cooperation related to the methanation project. Søren Dahl and Nan Topsøe from Haldor Topsøe are thanked for nice collaboration in relation to the SCR project. Within my private life in Denmark thanks is given to my family and friends-especially my parents, and my brother, Thomas, and my sister, Maria, should be mentioned here. A special thank is also given to Ulla, for always being a good friend, supportive and for listening to a lot of work/chemistry talk from time to time. My stay in the Netherlands has been one of the most inspiring and fruitful periods of my PhD. I am grateful to a lot of people for contributing to this. First of all to Professor Krijn de Jong who let me visit him and his research group at Universiteit Utrecht. From the first day I enjoyed the friendly, well-structured and intellectually inspiring atmosphere. I would also like to thank Associated Professor Harry Bitter for his interest in my work and for fruitful discussions. Special thanks should be given to Johan for showing me how everything works in the lab, being nice working together with and for helping with practical problems that arise when being in another country-including help with correcting and improving my Dutch. I would also like to thank Cor for helping with and explaining the TEM experiments. A few PhD students, Mariska, Adjan, Niels, Paul and Emiel, who have been extremely helpful with respect to experimental problems when needed, should be mentioned here too. Finally, I would like to thank all members of the Inorganic Chemistry and Catalysis group at Utrecht Universiteit for making my stay at the university a great time in coffee-breaks, at borrels etc. My social life outside work would not have been so cheerful if I had not met so many nice and kind Dutch people. I really appreciate both the company and the friendly help to correct and help me when speaking Dutch (and for talking English with me, when needed). Thus, I would like to thank all those who have contributed to making my time in Utrecht joyful. Furthermore, I would like to thank Kemisk Forenings Rejsefond, Otto Mønsteds Fond and Oticon Fonden for making my stay in the Netherlands economically possible.

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“…3,4 However, the zeolites are not very stable at high temperatures in moist feed, and sometimes their catalytic behaviour is affected by the binder substances used during the manufacturing of the extrusions. 5 Very recently, a zirconium-doped mesoporous silica, with an Si/Zr molar ratio of 5 (SiZr5), has been successfully tested as support for cobalt oxide 6 and copper oxide 7 in the SCR of NO using ammonia as the reducing agent. This modified mesoporous silica belongs to the well-known family of MCM-41 materials, 8 which present a hexagonal arrangement of cylindrical channels with diameters ranging between 16 and more than 100 A ˚.…”

Section: Introductionmentioning

confidence: 99%

“…Nickel oxide species are not generally used as active phases in the SCR of NO, but, recently, Ma et al 5 reported the preparation of a composite containing Ni-exchanged ZSM-5 supported on Raney-Ni, and they observed remarkable de-NO x activity when using ammonia as the reducing agent. The observed selectivity was even higher than that observed with a Cu-exchanged ZSM-5/Raney-Ni composite.…”

Section: Introductionmentioning

confidence: 99%

Nickel oxide supported on zirconium-doped mesoporous silica for selective catalytic reduction of NO with NH₃

et al. 2002

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Selective catalytic reduction of NO by ammonia over Raney-Ni supported Cu-ZSM-5

Cited by 18 publications

References 22 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

Design of Heterogeneous Catalysts

Nickel oxide supported on zirconium-doped mesoporous silica for selective catalytic reduction of NO with NH₃

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Selective catalytic reduction of NO by ammonia over Raney-Ni supported Cu-ZSM-5

Cited by 18 publications

References 22 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

Design of Heterogeneous Catalysts

Nickel oxide supported on zirconium-doped mesoporous silica for selective catalytic reduction of NO with NH3

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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

Nickel oxide supported on zirconium-doped mesoporous silica for selective catalytic reduction of NO with NH₃