Characterization of Fe/ZSM-5 by isotopic exchange with 18O2

T. V. Voskoboinikov; H. Y. Chen; W. M.H. Sachtler

doi:10.1016/S1381-1169(99)00331-3

Characterization of Fe/ZSM-5 by isotopic exchange with ¹⁸O₂

T. V. Voskoboinikov, H. Y. Chen, W. M.H. Sachtler

Research output: Contribution to journal › Article › peer-review

21 Scopus citations

Abstract

Exchange of ¹⁸O₂ with O atoms in two groups of Fe containing ZSM-5 catalysts was studied. One class was prepared by sublimation of FeCl₃ onto H-ZSM-5 with various Si/Al ratios. These materials are highly active and selective catalysts in the reduction of NO(x) with alkanes. A second group, further called Fe₂O₃/ZSM-5, was prepared by impregnation. Significant differences in the exchange behavior were found between both groups; the exchange rate is higher for Fe₂O₃/ZSM-5 than for Fe/ZSM-5, in accordance with the higher selectivity for alkane combustion of Fe₂O₃/ZSM-5 and its low selectivity for NO(x) reduction. The data suggest that negligible amounts of iron oxide particles exist in the Fe/ZSM-5 catalyst. For Fe/ZSM-5 catalysts the exchange is not limited to the oxygen atoms directly attached to iron; some zeolite oxygen is also exchanged, although this does not occur for the metal-free zeolite. Kinetic analysis shows that with Fe₂O₃/ZSM-5 the R² exchange mechanism prevails in which ¹⁸O₂ is exchanged in one step against two ¹⁶O atoms. For the selective Fe/ZSM-5 catalyst R¹ exchange prevails at low temperature, i.e., ¹⁸O₂ molecules exchange only one O atom against an atom of the solid. The qualitative difference between both types of catalyst indicates that Fe/ZSM-5 catalysts owe their selectivity in NO(x) reduction to Fe oxo-ions. (C) 2000 Elsevier Science B.V.

Original language	English
Pages (from-to)	155-168
Number of pages	14
Journal	Journal of Molecular Catalysis A: Chemical
Volume	155
Issue number	1-2
DOIs	https://doi.org/10.1016/S1381-1169(99)00331-3
State	Published - Apr 20 2000
Externally published	Yes

Funding

Financial support from the Director of the Chemistry Division, Basic Energy Sciences, U.S. Department of Energy, Grant DE-FG02-87ER13654, is gratefully acknowledged. We are also pleased to acknowledge support of UOP, Des Plaines, IL; and we thank Dr. Karin Bartels at Degussa and Dr. Arno Tißler of ALSI-PENTA Zeolithe, Schwandorf, Germany, for kindly donating ZSM-5 samples.

Funders	Funder number
U.S. Department of Energy	DE-FG02-87ER13654
Basic Energy Sciences

Keywords

Chemical vapor deposition
Exchange mechanisms
Fe/ZSM-5 catalyst
Oxygen isotope exchange
Selective reduction of NO(x)

Access to Document

10.1016/S1381-1169(99)00331-3

Cite this

@article{643f6e7a39384bd9a8d7e2e6446d04fd,

title = "Characterization of Fe/ZSM-5 by isotopic exchange with 18O2",

abstract = "Exchange of 18O2 with O atoms in two groups of Fe containing ZSM-5 catalysts was studied. One class was prepared by sublimation of FeCl3 onto H-ZSM-5 with various Si/Al ratios. These materials are highly active and selective catalysts in the reduction of NO(x) with alkanes. A second group, further called Fe2O3/ZSM-5, was prepared by impregnation. Significant differences in the exchange behavior were found between both groups; the exchange rate is higher for Fe2O3/ZSM-5 than for Fe/ZSM-5, in accordance with the higher selectivity for alkane combustion of Fe2O3/ZSM-5 and its low selectivity for NO(x) reduction. The data suggest that negligible amounts of iron oxide particles exist in the Fe/ZSM-5 catalyst. For Fe/ZSM-5 catalysts the exchange is not limited to the oxygen atoms directly attached to iron; some zeolite oxygen is also exchanged, although this does not occur for the metal-free zeolite. Kinetic analysis shows that with Fe2O3/ZSM-5 the R2 exchange mechanism prevails in which 18O2 is exchanged in one step against two 16O atoms. For the selective Fe/ZSM-5 catalyst R1 exchange prevails at low temperature, i.e., 18O2 molecules exchange only one O atom against an atom of the solid. The qualitative difference between both types of catalyst indicates that Fe/ZSM-5 catalysts owe their selectivity in NO(x) reduction to Fe oxo-ions. (C) 2000 Elsevier Science B.V.",

keywords = "Chemical vapor deposition, Exchange mechanisms, Fe/ZSM-5 catalyst, Oxygen isotope exchange, Selective reduction of NO(x)",

author = "Voskoboinikov, {T. V.} and Chen, {H. Y.} and Sachtler, {W. M.H.}",

year = "2000",

month = apr,

day = "20",

doi = "10.1016/S1381-1169(99)00331-3",

language = "English",

volume = "155",

pages = "155--168",

journal = "Journal of Molecular Catalysis A: Chemical",

issn = "1381-1169",

publisher = "Elsevier",

number = "1-2",

}

TY - JOUR

T1 - Characterization of Fe/ZSM-5 by isotopic exchange with 18O2

AU - Voskoboinikov, T. V.

AU - Chen, H. Y.

AU - Sachtler, W. M.H.

PY - 2000/4/20

Y1 - 2000/4/20

N2 - Exchange of 18O2 with O atoms in two groups of Fe containing ZSM-5 catalysts was studied. One class was prepared by sublimation of FeCl3 onto H-ZSM-5 with various Si/Al ratios. These materials are highly active and selective catalysts in the reduction of NO(x) with alkanes. A second group, further called Fe2O3/ZSM-5, was prepared by impregnation. Significant differences in the exchange behavior were found between both groups; the exchange rate is higher for Fe2O3/ZSM-5 than for Fe/ZSM-5, in accordance with the higher selectivity for alkane combustion of Fe2O3/ZSM-5 and its low selectivity for NO(x) reduction. The data suggest that negligible amounts of iron oxide particles exist in the Fe/ZSM-5 catalyst. For Fe/ZSM-5 catalysts the exchange is not limited to the oxygen atoms directly attached to iron; some zeolite oxygen is also exchanged, although this does not occur for the metal-free zeolite. Kinetic analysis shows that with Fe2O3/ZSM-5 the R2 exchange mechanism prevails in which 18O2 is exchanged in one step against two 16O atoms. For the selective Fe/ZSM-5 catalyst R1 exchange prevails at low temperature, i.e., 18O2 molecules exchange only one O atom against an atom of the solid. The qualitative difference between both types of catalyst indicates that Fe/ZSM-5 catalysts owe their selectivity in NO(x) reduction to Fe oxo-ions. (C) 2000 Elsevier Science B.V.

AB - Exchange of 18O2 with O atoms in two groups of Fe containing ZSM-5 catalysts was studied. One class was prepared by sublimation of FeCl3 onto H-ZSM-5 with various Si/Al ratios. These materials are highly active and selective catalysts in the reduction of NO(x) with alkanes. A second group, further called Fe2O3/ZSM-5, was prepared by impregnation. Significant differences in the exchange behavior were found between both groups; the exchange rate is higher for Fe2O3/ZSM-5 than for Fe/ZSM-5, in accordance with the higher selectivity for alkane combustion of Fe2O3/ZSM-5 and its low selectivity for NO(x) reduction. The data suggest that negligible amounts of iron oxide particles exist in the Fe/ZSM-5 catalyst. For Fe/ZSM-5 catalysts the exchange is not limited to the oxygen atoms directly attached to iron; some zeolite oxygen is also exchanged, although this does not occur for the metal-free zeolite. Kinetic analysis shows that with Fe2O3/ZSM-5 the R2 exchange mechanism prevails in which 18O2 is exchanged in one step against two 16O atoms. For the selective Fe/ZSM-5 catalyst R1 exchange prevails at low temperature, i.e., 18O2 molecules exchange only one O atom against an atom of the solid. The qualitative difference between both types of catalyst indicates that Fe/ZSM-5 catalysts owe their selectivity in NO(x) reduction to Fe oxo-ions. (C) 2000 Elsevier Science B.V.

KW - Chemical vapor deposition

KW - Exchange mechanisms

KW - Fe/ZSM-5 catalyst

KW - Oxygen isotope exchange

KW - Selective reduction of NO(x)

UR - http://www.scopus.com/inward/record.url?scp=0034690197&partnerID=8YFLogxK

U2 - 10.1016/S1381-1169(99)00331-3

DO - 10.1016/S1381-1169(99)00331-3

M3 - Article

AN - SCOPUS:0034690197

SN - 1381-1169

VL - 155

SP - 155

EP - 168

JO - Journal of Molecular Catalysis A: Chemical

JF - Journal of Molecular Catalysis A: Chemical

IS - 1-2

ER -