Observation of Sublattice Disordering of the Catalytic Sites in a Complex Mo-V-Nb-Te-O Oxidation Catalyst Using High Temperature STEM Imaging

Douglas A. Blom; Thomas Vogt; Larry F. Allard; Douglas J. Buttrey

doi:10.1007/s11244-014-0278-4

Observation of Sublattice Disordering of the Catalytic Sites in a Complex Mo-V-Nb-Te-O Oxidation Catalyst Using High Temperature STEM Imaging

Douglas A. Blom, Thomas Vogt, Larry F. Allard, Douglas J. Buttrey

Nuclear Energy Materials Microanalysis

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

28 Scopus citations

Abstract

A Mo-V-Nb-Te-O oxidation catalyst has been imaged using scanning transmission electron microscopy at 780 K, which is slightly above its operating temperature. We observe a sublattice disordering of the corner-sharing octahedra forming the catalytic sites containing V⁵⁺ while the edge-sharing pentagonal bipyramidal {Nb(Mo₅)} sublattice remains structurally more rigid and thereby maintains the overall structural integrity of the catalyst. Imaging the termination of the edges of the [001] basal zones at room temperature reveal a preference for presence of a closed network of secondary structural {Nb(Mo)₅} units providing further evidence of the stability of this sublattice structure. We propose that sublattice disordering of catalytic sites enables structural flexibility to accommodate different oxidation states during multistep chemical reactions within a more rigid superstructure and presents a new paradigm for compositionally and structurally complex catalysts.

Original language	English
Pages (from-to)	1138-1144
Number of pages	7
Journal	Topics in Catalysis
Volume	57
Issue number	14-16
DOIs	https://doi.org/10.1007/s11244-014-0278-4
State	Published - Sep 1 2014

Funding

Acknowledgments We thank the USC NanoCenter for financial support for beam time on the JEOL 2100 F and travel support to ORNL. We also thank A. F. Volpe Jr., C. G. Lugmair, and R. K. Grasselli for providing the M1 specimen used in this study. Microscopy research at the Oak Ridge National Laboratory was sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program, as part of the Propulsion Materials Program.

Funders	Funder number
U. S. Department of Energy
USC NanoCenter
Office of Energy Efficiency and Renewable Energy
Oak Ridge National Laboratory

Keywords

Active site
Ammoxidation
M1 phase
MoVNbTeO catalyst
STEM imaging
Selective oxidation
Sublattice disorder

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10.1007/s11244-014-0278-4

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title = "Observation of Sublattice Disordering of the Catalytic Sites in a Complex Mo-V-Nb-Te-O Oxidation Catalyst Using High Temperature STEM Imaging",

abstract = "A Mo-V-Nb-Te-O oxidation catalyst has been imaged using scanning transmission electron microscopy at 780 K, which is slightly above its operating temperature. We observe a sublattice disordering of the corner-sharing octahedra forming the catalytic sites containing V5+ while the edge-sharing pentagonal bipyramidal {Nb(Mo5)} sublattice remains structurally more rigid and thereby maintains the overall structural integrity of the catalyst. Imaging the termination of the edges of the [001] basal zones at room temperature reveal a preference for presence of a closed network of secondary structural {Nb(Mo)5} units providing further evidence of the stability of this sublattice structure. We propose that sublattice disordering of catalytic sites enables structural flexibility to accommodate different oxidation states during multistep chemical reactions within a more rigid superstructure and presents a new paradigm for compositionally and structurally complex catalysts.",

keywords = "Active site, Ammoxidation, M1 phase, MoVNbTeO catalyst, STEM imaging, Selective oxidation, Sublattice disorder",

author = "Blom, {Douglas A.} and Thomas Vogt and Allard, {Larry F.} and Buttrey, {Douglas J.}",

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AU - Blom, Douglas A.

AU - Vogt, Thomas

AU - Allard, Larry F.

AU - Buttrey, Douglas J.

PY - 2014/9/1

Y1 - 2014/9/1

N2 - A Mo-V-Nb-Te-O oxidation catalyst has been imaged using scanning transmission electron microscopy at 780 K, which is slightly above its operating temperature. We observe a sublattice disordering of the corner-sharing octahedra forming the catalytic sites containing V5+ while the edge-sharing pentagonal bipyramidal {Nb(Mo5)} sublattice remains structurally more rigid and thereby maintains the overall structural integrity of the catalyst. Imaging the termination of the edges of the [001] basal zones at room temperature reveal a preference for presence of a closed network of secondary structural {Nb(Mo)5} units providing further evidence of the stability of this sublattice structure. We propose that sublattice disordering of catalytic sites enables structural flexibility to accommodate different oxidation states during multistep chemical reactions within a more rigid superstructure and presents a new paradigm for compositionally and structurally complex catalysts.

AB - A Mo-V-Nb-Te-O oxidation catalyst has been imaged using scanning transmission electron microscopy at 780 K, which is slightly above its operating temperature. We observe a sublattice disordering of the corner-sharing octahedra forming the catalytic sites containing V5+ while the edge-sharing pentagonal bipyramidal {Nb(Mo5)} sublattice remains structurally more rigid and thereby maintains the overall structural integrity of the catalyst. Imaging the termination of the edges of the [001] basal zones at room temperature reveal a preference for presence of a closed network of secondary structural {Nb(Mo)5} units providing further evidence of the stability of this sublattice structure. We propose that sublattice disordering of catalytic sites enables structural flexibility to accommodate different oxidation states during multistep chemical reactions within a more rigid superstructure and presents a new paradigm for compositionally and structurally complex catalysts.

KW - Active site

KW - Ammoxidation

KW - M1 phase

KW - MoVNbTeO catalyst

KW - STEM imaging

KW - Selective oxidation

KW - Sublattice disorder

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ER -

Observation of Sublattice Disordering of the Catalytic Sites in a Complex Mo-V-Nb-Te-O Oxidation Catalyst Using High Temperature STEM Imaging

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Keywords

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