Reactivity of Fe-binuclear complexes in over-exchanged Fe/ZSM5, studied by in situ XAFS spectroscopy - Part 1: Heat treatment in He and O-2

AA Battiston; JH Bitter; WM Heijboer; FMF de Groot; DC Koningsberger

doi:10.1016/S0021-9517(02)00188-4

Reactivity of Fe-binuclear complexes in over-exchanged Fe/ZSM5, studied by in situ XAFS spectroscopy - Part 1: Heat treatment in He and O-2

AA Battiston, JH Bitter, WM Heijboer, FMF de Groot, DC Koningsberger^*

^*Corresponding author for this work

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

Abstract

The structure of the iron species in mildly calcined over-exchanged Fe/ZSM5, prepared by CVD of FeCl3, was studied during heat treatments in He or O-2/He (50:50) by coupling in situ Fe K edge HR-XANES and EXAFS. The majority of iron appears to be present as Fe-binuclear complexes. EXAFS shows that the closest Fe-O shell in the complexes can be described with a [HO-Fe-O-Fe-OH](2+) core. Heating to a moderate temperature (up to similar to150degreesC) results in the desorption of water from the Fe-coordination sphere, in He as well as in a O-2/He (50:50) mixture. The composition of the gas phase strongly influences the changes occurring to the binuclear complexes in the 150-350degreesC temperature range. Above 250degreesC in He a significant fraction of iron undergoes autoreduction. This is accompanied by the removal of approximately one oxygen atom from the closest Fe-O shell, ascribable to the Fe-O-Fe bridging oxygen atom. The presence of oxygen in the gas phase (PO2 = 0.5 bar), on the contrary, suppresses the auto-reduction capability of the binuclear complexes by inhibiting the removal of the Fe-O-Fe bridging oxygen. (C) 2003 Elsevier Science (USA). All rights reserved.

Original language	English
Pages (from-to)	279-293
Number of pages	15
Journal	Journal of Catalysis
Volume	215
Issue number	2
DOIs	https://doi.org/10.1016/S0021-9517(02)00188-4
Publication status	Published - 25 Apr 2003

Keywords

Fe/ZSM5
binuclear
iron
red-ox properties
auto-reduction
reactivity
helium
oxygen
ABSORPTION FINE-STRUCTURE
NOX REDUCTION
ACTIVE-SITES
METHANE MONOOXYGENASE
ADSORPTION COMPLEXES
FE/MFI CATALYSTS
IRON COMPLEXES
N2O
ZEOLITES
FEZSM-5

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title = "Reactivity of Fe-binuclear complexes in over-exchanged Fe/ZSM5, studied by in situ XAFS spectroscopy - Part 1: Heat treatment in He and O-2",

abstract = "The structure of the iron species in mildly calcined over-exchanged Fe/ZSM5, prepared by CVD of FeCl3, was studied during heat treatments in He or O-2/He (50:50) by coupling in situ Fe K edge HR-XANES and EXAFS. The majority of iron appears to be present as Fe-binuclear complexes. EXAFS shows that the closest Fe-O shell in the complexes can be described with a [HO-Fe-O-Fe-OH](2+) core. Heating to a moderate temperature (up to similar to150degreesC) results in the desorption of water from the Fe-coordination sphere, in He as well as in a O-2/He (50:50) mixture. The composition of the gas phase strongly influences the changes occurring to the binuclear complexes in the 150-350degreesC temperature range. Above 250degreesC in He a significant fraction of iron undergoes autoreduction. This is accompanied by the removal of approximately one oxygen atom from the closest Fe-O shell, ascribable to the Fe-O-Fe bridging oxygen atom. The presence of oxygen in the gas phase (PO2 = 0.5 bar), on the contrary, suppresses the auto-reduction capability of the binuclear complexes by inhibiting the removal of the Fe-O-Fe bridging oxygen. (C) 2003 Elsevier Science (USA). All rights reserved.",

keywords = "Fe/ZSM5, binuclear, iron, red-ox properties, auto-reduction, reactivity, helium, oxygen, ABSORPTION FINE-STRUCTURE, NOX REDUCTION, ACTIVE-SITES, METHANE MONOOXYGENASE, ADSORPTION COMPLEXES, FE/MFI CATALYSTS, IRON COMPLEXES, N2O, ZEOLITES, FEZSM-5",

author = "AA Battiston and JH Bitter and WM Heijboer and {de Groot}, FMF and DC Koningsberger",

year = "2003",

month = apr,

day = "25",

doi = "10.1016/S0021-9517(02)00188-4",

language = "English",

volume = "215",

pages = "279--293",

journal = "Journal of Catalysis",

issn = "0021-9517",

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TY - JOUR

T1 - Reactivity of Fe-binuclear complexes in over-exchanged Fe/ZSM5, studied by in situ XAFS spectroscopy - Part 1

T2 - Heat treatment in He and O-2

AU - Battiston, AA

AU - Bitter, JH

AU - Heijboer, WM

AU - de Groot, FMF

AU - Koningsberger, DC

PY - 2003/4/25

Y1 - 2003/4/25

N2 - The structure of the iron species in mildly calcined over-exchanged Fe/ZSM5, prepared by CVD of FeCl3, was studied during heat treatments in He or O-2/He (50:50) by coupling in situ Fe K edge HR-XANES and EXAFS. The majority of iron appears to be present as Fe-binuclear complexes. EXAFS shows that the closest Fe-O shell in the complexes can be described with a [HO-Fe-O-Fe-OH](2+) core. Heating to a moderate temperature (up to similar to150degreesC) results in the desorption of water from the Fe-coordination sphere, in He as well as in a O-2/He (50:50) mixture. The composition of the gas phase strongly influences the changes occurring to the binuclear complexes in the 150-350degreesC temperature range. Above 250degreesC in He a significant fraction of iron undergoes autoreduction. This is accompanied by the removal of approximately one oxygen atom from the closest Fe-O shell, ascribable to the Fe-O-Fe bridging oxygen atom. The presence of oxygen in the gas phase (PO2 = 0.5 bar), on the contrary, suppresses the auto-reduction capability of the binuclear complexes by inhibiting the removal of the Fe-O-Fe bridging oxygen. (C) 2003 Elsevier Science (USA). All rights reserved.

AB - The structure of the iron species in mildly calcined over-exchanged Fe/ZSM5, prepared by CVD of FeCl3, was studied during heat treatments in He or O-2/He (50:50) by coupling in situ Fe K edge HR-XANES and EXAFS. The majority of iron appears to be present as Fe-binuclear complexes. EXAFS shows that the closest Fe-O shell in the complexes can be described with a [HO-Fe-O-Fe-OH](2+) core. Heating to a moderate temperature (up to similar to150degreesC) results in the desorption of water from the Fe-coordination sphere, in He as well as in a O-2/He (50:50) mixture. The composition of the gas phase strongly influences the changes occurring to the binuclear complexes in the 150-350degreesC temperature range. Above 250degreesC in He a significant fraction of iron undergoes autoreduction. This is accompanied by the removal of approximately one oxygen atom from the closest Fe-O shell, ascribable to the Fe-O-Fe bridging oxygen atom. The presence of oxygen in the gas phase (PO2 = 0.5 bar), on the contrary, suppresses the auto-reduction capability of the binuclear complexes by inhibiting the removal of the Fe-O-Fe bridging oxygen. (C) 2003 Elsevier Science (USA). All rights reserved.

KW - Fe/ZSM5

KW - binuclear

KW - iron

KW - red-ox properties

KW - auto-reduction

KW - reactivity

KW - helium

KW - oxygen

KW - ABSORPTION FINE-STRUCTURE

KW - NOX REDUCTION

KW - ACTIVE-SITES

KW - METHANE MONOOXYGENASE

KW - ADSORPTION COMPLEXES

KW - FE/MFI CATALYSTS

KW - IRON COMPLEXES

KW - N2O

KW - ZEOLITES

KW - FEZSM-5

U2 - 10.1016/S0021-9517(02)00188-4

DO - 10.1016/S0021-9517(02)00188-4

M3 - Article

SN - 0021-9517

VL - 215

SP - 279

EP - 293

JO - Journal of Catalysis

JF - Journal of Catalysis

IS - 2

ER -

Reactivity of Fe-binuclear complexes in over-exchanged Fe/ZSM5, studied by in situ XAFS spectroscopy - Part 1: Heat treatment in He and O-2

Abstract

Keywords

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