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Title: Fe/ZSM-5 prepared by sublimination of FeCl{sub 3}: The structure of the Fe species as determined by IR, {sup 27}Al MAS NMR, and EXAFS spectroscopy

Abstract

The state of the iron in two different Fe/ZSM-5 samples prepared by sublimation of FeCl{sub 3} was investigated by EXAFS, IR, {sup 27}Al MAS NMR, XRD, and nitrogen adsorption measurements. In one Fe/ZSM-54 (Fe/Al = 1) sample, EXAFS revealed for the first time the presence of diferric (hydr)oxo-bridged binuclear clusters, whose structures differ from those postulated in the literature, resembling that of the methane monooxygenase enzyme. IR showed that binuclear Fe complexes are located at the ion-exchange positions of the zeolite, compensating one or two lattice charges. The remainder of the charge-compensating one or two lattice charges. The remainder of the charge-compensating sites are Broensted hydroxyls. On both zeolites, the NMR detection of the framework Al atoms (54 ppm) is strongly perturbed by the paramagnetic effects induced by the Fe ions. The intensity of this peak parallels that of the Broensted hydroxyls in the IR spectra, thus reflecting the presence of Fe species at ion-exchange positions. In a second Fe/ZSM-5 (Fe/Al = 0.8) sample, the iron was present predominantly in the form of large hematite particles (EXAFS, XRD), although a minor fraction of binuclear species might be present as well. The formation of different species seems to be related tomore » different hydrolysis processes occurring on the two zeolites upon washing of the preparation after the sublimation of FeCl{sub 3}. It is also suggested that the final state of the Fe depends on the presence of extraframework Al species as well as the crystallite size of the zeolite used.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Swiss Federal Inst. of Tech., Zuerich (CH)
OSTI Identifier:
20076106
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 192; Journal Issue: 1; Other Information: PBD: 15 May 2000; Journal ID: ISSN 0021-9517
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 01 COAL, LIGNITE, AND PEAT; IRON; ZEOLITES; CHEMICAL PREPARATION; MORPHOLOGY; SUBLIMATION; IRON CHLORIDES; CATALYSTS; NITROGEN OXIDES; SELECTIVE CATALYTIC REDUCTION; AIR POLLUTION CONTROL

Citation Formats

Marturano, P., Drozdova, L., Kogelbauer, A., and Prins, R. Fe/ZSM-5 prepared by sublimination of FeCl{sub 3}: The structure of the Fe species as determined by IR, {sup 27}Al MAS NMR, and EXAFS spectroscopy. United States: N. p., 2000. Web. doi:10.1006/jcat.2000.2837.
Marturano, P., Drozdova, L., Kogelbauer, A., & Prins, R. Fe/ZSM-5 prepared by sublimination of FeCl{sub 3}: The structure of the Fe species as determined by IR, {sup 27}Al MAS NMR, and EXAFS spectroscopy. United States. doi:10.1006/jcat.2000.2837.
Marturano, P., Drozdova, L., Kogelbauer, A., and Prins, R. Mon . "Fe/ZSM-5 prepared by sublimination of FeCl{sub 3}: The structure of the Fe species as determined by IR, {sup 27}Al MAS NMR, and EXAFS spectroscopy". United States. doi:10.1006/jcat.2000.2837.
@article{osti_20076106,
title = {Fe/ZSM-5 prepared by sublimination of FeCl{sub 3}: The structure of the Fe species as determined by IR, {sup 27}Al MAS NMR, and EXAFS spectroscopy},
author = {Marturano, P. and Drozdova, L. and Kogelbauer, A. and Prins, R.},
abstractNote = {The state of the iron in two different Fe/ZSM-5 samples prepared by sublimation of FeCl{sub 3} was investigated by EXAFS, IR, {sup 27}Al MAS NMR, XRD, and nitrogen adsorption measurements. In one Fe/ZSM-54 (Fe/Al = 1) sample, EXAFS revealed for the first time the presence of diferric (hydr)oxo-bridged binuclear clusters, whose structures differ from those postulated in the literature, resembling that of the methane monooxygenase enzyme. IR showed that binuclear Fe complexes are located at the ion-exchange positions of the zeolite, compensating one or two lattice charges. The remainder of the charge-compensating one or two lattice charges. The remainder of the charge-compensating sites are Broensted hydroxyls. On both zeolites, the NMR detection of the framework Al atoms (54 ppm) is strongly perturbed by the paramagnetic effects induced by the Fe ions. The intensity of this peak parallels that of the Broensted hydroxyls in the IR spectra, thus reflecting the presence of Fe species at ion-exchange positions. In a second Fe/ZSM-5 (Fe/Al = 0.8) sample, the iron was present predominantly in the form of large hematite particles (EXAFS, XRD), although a minor fraction of binuclear species might be present as well. The formation of different species seems to be related to different hydrolysis processes occurring on the two zeolites upon washing of the preparation after the sublimation of FeCl{sub 3}. It is also suggested that the final state of the Fe depends on the presence of extraframework Al species as well as the crystallite size of the zeolite used.},
doi = {10.1006/jcat.2000.2837},
journal = {Journal of Catalysis},
issn = {0021-9517},
number = 1,
volume = 192,
place = {United States},
year = {2000},
month = {5}
}