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Operando XAFS studies reveals differences in the activity of Fe-species in MFI and CHA structures for the standard selective catalytic reduction of NO with NH3
DOI:
10.1016/j.apcata.2018.11.026
Authors:
Miren
Agote-Aran
(University College of London; Research Complex at Harwell; Diamond Light Source)
,
Ines
Lezcano-Gonzalez
(University College London; Research Complex at Harwell)
,
Alex G.
Greenaway
(University College London; Research Complex at Harwell)
,
Shusaku
Hayama
(Diamond Light Source)
,
Sofia
Diaz-Moreno
(Diamond Light Source)
,
Anna B.
Kroner
(Diamond Light Source)
,
Andrew M.
Beale
(University College London; Research Complex at Harwell)
Co-authored by industrial partner:
No
Type:
Journal Paper
Journal:
Applied Catalysis A: General
State:
Published (Approved)
Published:
November 2018
Diamond Proposal Number(s):
9925

Abstract: Fe-containing zeolites were studied as catalysts for the standard NH3-SCR reaction with the primary aim of gaining insight into the structure-function relationship of these materials. Catalysts with different Fe nuclearity (i.e. isolated species, clusters, large particles) were synthesised by incipient wetness impregnation, using H-ZSM-5, H-SSZ-13 and Silicalite-1 as supports, and characterised by in situ and operando X-ray emission spectroscopy (XES) and high energy resolution fluorescence detected X-ray absorption near-edge spectroscopy (HERFD-XANES) under NH3-SCR conditions. The combination of these techniques allowed us to obtain a detailed understanding of the changes in Fe coordination, oxidation state and geometry occurring during reaction. The results obtained suggested that isolated octahedral Fe3+ species on H-ZSM-5 are highly active under the conditions studied, undergoing reduction when exposed to NH3 or under SCR conditions. In contrast, isolated tetrahedral Fe3+ sites present in Silicalite-1 exhibited lower redox properties, leading to a reduced NO conversion. Clusters and FexOy particles on H-SSZ-13 exhibited low SCR activity.
Journal Keywords: NH3-SCR; NO; Fe-containing zeolites; HERFD-XANES; XES
Subject Areas:
Chemistry,
Materials
Instruments:
I20-Scanning-X-ray spectroscopy (XAS/XES)
Added On:
28/11/2018 09:04
Documents:
1-s2.0-S0926860X18305817-main.pdf
Discipline Tags:
Zeolites
Physical Chemistry
Catalysis
Chemistry
Materials Science
Technical Tags:
Spectroscopy
X-ray Absorption Spectroscopy (XAS)
X-ray Emission Spectroscopy (XES)
High Energy Resolution Fluorescence Detected XAS (HERFD-XAS)