Catalytic performance of sheet-like Fe/ZSM-5 zeolites for the selective oxidation of benzene with nitrous oxide

A.J.J. Koekkoek, W. Kim, V. Degirmenci, H. Xin, R. Ryoo, E.J.M. Hensen

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Abstract

Hierarchical Fe/ZSM-5 zeolites were synthesized with a diquaternary ammonium surfactant containing a hydrophobic tail and extensively characterized by XRD, Ar porosimetry, TEM, DRUV–Vis, and UV-Raman spectroscopy. Their catalytic activities in catalytic decomposition of N2O and the oxidation of benzene to phenol with N2O as the oxidant were also determined. The hierarchical zeolites consist of thin sheets limited in growth in the b-direction (along the straight channels of the MFI network) and exhibit similar high hydrothermal stability as a reference Fe/ZSM-5 zeolite. Spectroscopic and catalytic investigations point to subtle differences in the extent of Fe agglomeration with the sheet-like zeolites having a higher proportion of isolated Fe centers than the reference zeolite. As a consequence, these zeolites have a somewhat lower activity in catalytic N2O decomposition (catalyzed by oligomeric Fe), but display higher activity in benzene oxidation (catalyzed by monomeric Fe). The sheet-like zeolites deactivate much slower than bulk Fe/ZSM-5, which is attributed to the much lower probability of secondary reactions of phenol in the short straight channels of the sheets. The deactivation rate decreases with decreasing Fe content of the Fe/ZSM-5 nanosheets. It is found that carbonaceous materials are mainly deposited in the mesopores between the nanosheets and much less so in the micropores. This contrasts the strong decrease in the micropore volume of bulk Fe/ZSM-5 due to rapid clogging of the continuous micropore network. The formation of coke deposits is limited in the nanosheet zeolites because of the short molecular trafficking distances. It is argued that at high Si/Fe content, coke deposits mainly form on the external surface of the nanosheets.
Original languageEnglish
Pages (from-to)81-89
Number of pages9
JournalJournal of Catalysis
Volume299
DOIs
Publication statusPublished - 2013

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Zeolites
nitrous oxides
Nitrous Oxide
Benzene
zeolites
Nanosheets
benzene
Oxidation
oxidation
Oxides
coke
Coke
phenols
Phenols
Phenol
Deposits
deposits
Decomposition
decomposition
carbonaceous materials

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title = "Catalytic performance of sheet-like Fe/ZSM-5 zeolites for the selective oxidation of benzene with nitrous oxide",
abstract = "Hierarchical Fe/ZSM-5 zeolites were synthesized with a diquaternary ammonium surfactant containing a hydrophobic tail and extensively characterized by XRD, Ar porosimetry, TEM, DRUV–Vis, and UV-Raman spectroscopy. Their catalytic activities in catalytic decomposition of N2O and the oxidation of benzene to phenol with N2O as the oxidant were also determined. The hierarchical zeolites consist of thin sheets limited in growth in the b-direction (along the straight channels of the MFI network) and exhibit similar high hydrothermal stability as a reference Fe/ZSM-5 zeolite. Spectroscopic and catalytic investigations point to subtle differences in the extent of Fe agglomeration with the sheet-like zeolites having a higher proportion of isolated Fe centers than the reference zeolite. As a consequence, these zeolites have a somewhat lower activity in catalytic N2O decomposition (catalyzed by oligomeric Fe), but display higher activity in benzene oxidation (catalyzed by monomeric Fe). The sheet-like zeolites deactivate much slower than bulk Fe/ZSM-5, which is attributed to the much lower probability of secondary reactions of phenol in the short straight channels of the sheets. The deactivation rate decreases with decreasing Fe content of the Fe/ZSM-5 nanosheets. It is found that carbonaceous materials are mainly deposited in the mesopores between the nanosheets and much less so in the micropores. This contrasts the strong decrease in the micropore volume of bulk Fe/ZSM-5 due to rapid clogging of the continuous micropore network. The formation of coke deposits is limited in the nanosheet zeolites because of the short molecular trafficking distances. It is argued that at high Si/Fe content, coke deposits mainly form on the external surface of the nanosheets.",
author = "A.J.J. Koekkoek and W. Kim and V. Degirmenci and H. Xin and R. Ryoo and E.J.M. Hensen",
year = "2013",
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language = "English",
volume = "299",
pages = "81--89",
journal = "Journal of Catalysis",
issn = "0021-9517",
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}

Catalytic performance of sheet-like Fe/ZSM-5 zeolites for the selective oxidation of benzene with nitrous oxide. / Koekkoek, A.J.J.; Kim, W.; Degirmenci, V.; Xin, H.; Ryoo, R.; Hensen, E.J.M.

In: Journal of Catalysis, Vol. 299, 2013, p. 81-89.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Catalytic performance of sheet-like Fe/ZSM-5 zeolites for the selective oxidation of benzene with nitrous oxide

AU - Koekkoek, A.J.J.

AU - Kim, W.

AU - Degirmenci, V.

AU - Xin, H.

AU - Ryoo, R.

AU - Hensen, E.J.M.

PY - 2013

Y1 - 2013

N2 - Hierarchical Fe/ZSM-5 zeolites were synthesized with a diquaternary ammonium surfactant containing a hydrophobic tail and extensively characterized by XRD, Ar porosimetry, TEM, DRUV–Vis, and UV-Raman spectroscopy. Their catalytic activities in catalytic decomposition of N2O and the oxidation of benzene to phenol with N2O as the oxidant were also determined. The hierarchical zeolites consist of thin sheets limited in growth in the b-direction (along the straight channels of the MFI network) and exhibit similar high hydrothermal stability as a reference Fe/ZSM-5 zeolite. Spectroscopic and catalytic investigations point to subtle differences in the extent of Fe agglomeration with the sheet-like zeolites having a higher proportion of isolated Fe centers than the reference zeolite. As a consequence, these zeolites have a somewhat lower activity in catalytic N2O decomposition (catalyzed by oligomeric Fe), but display higher activity in benzene oxidation (catalyzed by monomeric Fe). The sheet-like zeolites deactivate much slower than bulk Fe/ZSM-5, which is attributed to the much lower probability of secondary reactions of phenol in the short straight channels of the sheets. The deactivation rate decreases with decreasing Fe content of the Fe/ZSM-5 nanosheets. It is found that carbonaceous materials are mainly deposited in the mesopores between the nanosheets and much less so in the micropores. This contrasts the strong decrease in the micropore volume of bulk Fe/ZSM-5 due to rapid clogging of the continuous micropore network. The formation of coke deposits is limited in the nanosheet zeolites because of the short molecular trafficking distances. It is argued that at high Si/Fe content, coke deposits mainly form on the external surface of the nanosheets.

AB - Hierarchical Fe/ZSM-5 zeolites were synthesized with a diquaternary ammonium surfactant containing a hydrophobic tail and extensively characterized by XRD, Ar porosimetry, TEM, DRUV–Vis, and UV-Raman spectroscopy. Their catalytic activities in catalytic decomposition of N2O and the oxidation of benzene to phenol with N2O as the oxidant were also determined. The hierarchical zeolites consist of thin sheets limited in growth in the b-direction (along the straight channels of the MFI network) and exhibit similar high hydrothermal stability as a reference Fe/ZSM-5 zeolite. Spectroscopic and catalytic investigations point to subtle differences in the extent of Fe agglomeration with the sheet-like zeolites having a higher proportion of isolated Fe centers than the reference zeolite. As a consequence, these zeolites have a somewhat lower activity in catalytic N2O decomposition (catalyzed by oligomeric Fe), but display higher activity in benzene oxidation (catalyzed by monomeric Fe). The sheet-like zeolites deactivate much slower than bulk Fe/ZSM-5, which is attributed to the much lower probability of secondary reactions of phenol in the short straight channels of the sheets. The deactivation rate decreases with decreasing Fe content of the Fe/ZSM-5 nanosheets. It is found that carbonaceous materials are mainly deposited in the mesopores between the nanosheets and much less so in the micropores. This contrasts the strong decrease in the micropore volume of bulk Fe/ZSM-5 due to rapid clogging of the continuous micropore network. The formation of coke deposits is limited in the nanosheet zeolites because of the short molecular trafficking distances. It is argued that at high Si/Fe content, coke deposits mainly form on the external surface of the nanosheets.

U2 - 10.1016/j.jcat.2012.12.002

DO - 10.1016/j.jcat.2012.12.002

M3 - Article

VL - 299

SP - 81

EP - 89

JO - Journal of Catalysis

JF - Journal of Catalysis

SN - 0021-9517

ER -