Visualizing atomic-scale redox dynamics in vanadium oxide-based catalysts

Surface redox processes involving oxygen atom exchange are fundamental in catalytic reactions mediated by metal oxides. These processes are often difficult to uncover due to changes in the surface stoichiometry and atomic arrangement. Here we employ high-resolution transmission electron microscopy t...

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Bibliographic Details
Published in:Nature communications 2017-08, Vol.8 (1), p.305-9, Article 305
Main Authors: Ek, Martin, Ramasse, Quentin M., Arnarson, Logi, Georg Moses, Poul, Helveg, Stig
Format: Article
Language:English
Subjects:
639/301/299
639/638/77/887
639/925/357/354
639/925/357/537
639/925/930/328/2082
Atomic structure
Catalysts
Electrons
Heat detection
Humanities and Social Sciences
multidisciplinary
Oxidation
Scale (corrosion)
Science
Science (multidisciplinary)
Vanadium
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Summary:Surface redox processes involving oxygen atom exchange are fundamental in catalytic reactions mediated by metal oxides. These processes are often difficult to uncover due to changes in the surface stoichiometry and atomic arrangement. Here we employ high-resolution transmission electron microscopy to study vanadium oxide supported on titanium dioxide, which is of relevance as a catalyst in, e.g., nitrogen oxide emission abatement for environmental protection. The observations reveal a reversible transformation of the vanadium oxide surface between an ordered and disordered state, concomitant with a reversible change in the vanadium oxidation state, when alternating between oxidizing and reducing conditions. The transformation depends on the anatase titanium dioxide surface termination and the vanadium oxide layer thickness, suggesting that the properties of vanadium oxide are sensitive to the supporting oxide. These atomic-resolution observations offer a basis for rationalizing previous reports on shape-sensitive catalytic properties. Redox processes in metal oxide surfaces can exhibit structure sensitivities which are difficult to uncover. Here, the authors use atomic-resolution imaging to demonstrate facet dependent alterations in the surfaces of supported vanadium oxide upon reduction and oxidation.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-017-00385-y