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Structural dynamics in Ni–Fe catalysts during CO₂ methanation - role of iron oxide clusters

Serrer, Marc-André; Gaur, Abhijeet; Jelic, Jelena; Weber, Sebastian; Fritsch, Charlotte; Clark, Adam H.; Saraçi, Erisa; Studt, Felix; Grunwaldt, Jan-Dierk

Abstract:
Bimetallic Ni–Fe catalysts show great potential for CO$_{2}$ methanation concerning activity, selectivity and long-term stability even under transient reaction conditions as required for Power-to-X applications. Various contrary suggestions on the role of iron in this system on CO$_{2}$ activation have been proposed, hence, its actual task remained still unclear. In this study, we used X-ray absorption spectroscopy (XAS) combined with X-ray diffraction (XRD), XAS in combination with modulation excitation spectroscopy (MES) and density functional theory (DFT) to shed detailed light on the role of iron in a bimetallic Ni–Fe based CO$_{2}$ methanation catalyst. During catalyst activation we observed a synergistic effect between nickel and iron that led to higher fractions of reduced nickel compared to a monometallic Ni-based catalyst. By XAS–XRD combined with DFT, we found formation of FeO$_{x}$ clusters on top of the metal particles. Modulation excitation coupled XAS data complemented with DFT calculations provided evidence of a Fe$^{0}$ ⇌ Fe$^{2+}$+ ⇌ Fe$^{3+}$ redox mechanism at the interface of these FeO$_{x}$ clusters. This may promote CO$_{2}$ dissociation. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000124247
Veröffentlicht am 21.02.2021
Originalveröffentlichung
DOI: 10.1039/D0CY01396J
Dimensions
Zitationen: 9
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Katalyseforschung und -technologie (IKFT)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2044-4753, 2044-4761
KITopen-ID: 1000124247
HGF-Programm 37.03.01 (POF III, LK 01) Catalysts and Mechanisms
Erschienen in Catalysis science & technology
Verlag Royal Society of Chemistry (RSC)
Band 10
Heft 22
Seiten 7542-7554
Vorab online veröffentlicht am 30.09.2020
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