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Quality or quantity? How structural parameters affect catalytic activity of iron oxides for CO oxidation

DOI: 10.3390/catal12060675 DOI Help

Authors: Steffen Schlicher (Paderborn University) , Nils Prinz (RWTH Aachen University) , Julius Bürger (Paderborn University) , Andreas Omlor (Technical University of Kaiserslautern) , Christian Singer (Technical University of Freiberg) , Mirijam Zobel (RWTH Aachen University) , Roland Schoch (Paderborn University) , Jörg K. N. Lindner (Paderborn University) , Volker Schünemann (Technical University of Kaiserslautern) , Sven Kureti (Technical University of Freiberg) , Matthias Bauer (Paderborn University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Catalysts , VOL 12

State: Published (Approved)
Published: June 2022
Diamond Proposal Number(s): 20578

Open Access Open Access

Abstract: The replacement of noble metal catalysts by abundant iron as an active compound in CO oxidation is of ecologic and economic interest. However, improvement of their catalytic performance to the same level as state-of-the-art noble metal catalysts requires an in depth understanding of their working principle on an atomic level. As a contribution to this aim, a series of iron oxide catalysts with varying Fe loadings from 1 to 20 wt% immobilized on a γ-Al2O3 support is presented here, and a multidimensional structure–activity correlation is established. The CO oxidation activity is correlated to structural details obtained by various spectroscopic, diffraction, and microscopic methods, such as PXRD, PDF analysis, DRUVS, Mössbauer spectroscopy, STEM-EDX, and XAS. Low Fe loadings lead to less agglomerated but high percentual amounts of isolated, tetrahedrally coordinated iron oxide species, while the absolute amount of isolated species reaches its maximum at high Fe loadings. Consequently, the highest CO oxidation activity in terms of turnover frequencies can be correlated to small, finely dispersed iron oxide species with a large amount of tetrahedrally oxygen coordinated iron sites, while the overall amount of isolated iron oxide species correlates with a lower light-off temperature.

Journal Keywords: CO oxidation; iron oxide; emission control; PDF; STEM-EDX mapping; XAS

Subject Areas: Chemistry

Instruments: I15-1-X-ray Pair Distribution Function (XPDF)

Other Facilities: P24, P65 at DESY

Added On: 27/06/2022 11:36


Discipline Tags:

Physical Chemistry Catalysis Chemistry

Technical Tags:

Scattering Pair Distribution Function (PDF)