Characterization of V-Mo-W Mixed Oxide Catalyst Surface Species by 51V Solid-State Dynamic Nuclear Polarization NMR

Aany S.L. Thankamony; Stefan Knoche; Sarah Bothe; Alfons Drochner; Anil P. Jagtap; Snorri Th Sigurdsson; Herbert Vogel; Bastian J.M. Etzold; Torsten Gutmann; Gerd Buntkowsky

doi:10.1021/acs.jpcc.7b06761

Characterization of V-Mo-W Mixed Oxide Catalyst Surface Species by ⁵¹V Solid-State Dynamic Nuclear Polarization NMR

Aany S.L. Thankamony, Stefan Knoche, Sarah Bothe, Alfons Drochner, Anil P. Jagtap, Snorri Th Sigurdsson, Herbert Vogel, Bastian J.M. Etzold, Torsten Gutmann^*, Gerd Buntkowsky

^*Corresponding author for this work

Faculty of Physical Sciences

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

10 Citations (Scopus)

Abstract

The investigation of V-Mo-W mixed oxide catalysts by ⁵¹V DNP MAS NMR is reported. It is shown that the ⁵¹V NMR signal from surface near vanadium nuclei was enhanced by a factor of ≈50 by direct polarization transfer from unpaired electrons to ⁵¹V nuclei. The dependency of the DNP enhancement of the samples on different polarizing mixtures is investigated and complemented by EPR studies. V-Mo-W mixed oxide catalysts with different stoichiometry (V₂Mo₈W_0.5O_y, V₂Mo₈W₁O_y, and V₂Mo₈W_1.5O_y) are compared, and a suitable assignment of ⁵¹V signals to different phases that are present near to the catalysts surfaces is given. Finally, the applicability of DNP solid-state NMR for the characterization of V-Mo-W mixed oxide catalysts is discussed in terms of the synthesis conditions (i.e., pH-value). (Graph Presented).

Original language	English
Pages (from-to)	20857-20864
Number of pages	8
Journal	Journal of Physical Chemistry C
Volume	121
Issue number	38
DOIs	https://doi.org/10.1021/acs.jpcc.7b06761
Publication status	Published - 28 Sep 2017

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Publisher Copyright:
© 2017 American Chemical Society.

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10.1021/acs.jpcc.7b06761

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Thankamony, A. S. L., Knoche, S., Bothe, S., Drochner, A., Jagtap, A. P., Sigurdsson, S. T., Vogel, H., Etzold, B. J. M., Gutmann, T., & Buntkowsky, G. (2017). Characterization of V-Mo-W Mixed Oxide Catalyst Surface Species by ⁵¹V Solid-State Dynamic Nuclear Polarization NMR. Journal of Physical Chemistry C, 121(38), 20857-20864. https://doi.org/10.1021/acs.jpcc.7b06761

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title = "Characterization of V-Mo-W Mixed Oxide Catalyst Surface Species by 51V Solid-State Dynamic Nuclear Polarization NMR",

abstract = "The investigation of V-Mo-W mixed oxide catalysts by 51V DNP MAS NMR is reported. It is shown that the 51V NMR signal from surface near vanadium nuclei was enhanced by a factor of ≈50 by direct polarization transfer from unpaired electrons to 51V nuclei. The dependency of the DNP enhancement of the samples on different polarizing mixtures is investigated and complemented by EPR studies. V-Mo-W mixed oxide catalysts with different stoichiometry (V2Mo8W0.5Oy, V2Mo8W1Oy, and V2Mo8W1.5Oy) are compared, and a suitable assignment of 51V signals to different phases that are present near to the catalysts surfaces is given. Finally, the applicability of DNP solid-state NMR for the characterization of V-Mo-W mixed oxide catalysts is discussed in terms of the synthesis conditions (i.e., pH-value). (Graph Presented).",

author = "Thankamony, {Aany S.L.} and Stefan Knoche and Sarah Bothe and Alfons Drochner and Jagtap, {Anil P.} and Sigurdsson, {Snorri Th} and Herbert Vogel and Etzold, {Bastian J.M.} and Torsten Gutmann and Gerd Buntkowsky",

note = "Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",

year = "2017",

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doi = "10.1021/acs.jpcc.7b06761",

language = "English",

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AU - Thankamony, Aany S.L.

AU - Knoche, Stefan

AU - Bothe, Sarah

AU - Drochner, Alfons

AU - Jagtap, Anil P.

AU - Sigurdsson, Snorri Th

AU - Vogel, Herbert

AU - Etzold, Bastian J.M.

AU - Gutmann, Torsten

AU - Buntkowsky, Gerd

PY - 2017/9/28

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N2 - The investigation of V-Mo-W mixed oxide catalysts by 51V DNP MAS NMR is reported. It is shown that the 51V NMR signal from surface near vanadium nuclei was enhanced by a factor of ≈50 by direct polarization transfer from unpaired electrons to 51V nuclei. The dependency of the DNP enhancement of the samples on different polarizing mixtures is investigated and complemented by EPR studies. V-Mo-W mixed oxide catalysts with different stoichiometry (V2Mo8W0.5Oy, V2Mo8W1Oy, and V2Mo8W1.5Oy) are compared, and a suitable assignment of 51V signals to different phases that are present near to the catalysts surfaces is given. Finally, the applicability of DNP solid-state NMR for the characterization of V-Mo-W mixed oxide catalysts is discussed in terms of the synthesis conditions (i.e., pH-value). (Graph Presented).

AB - The investigation of V-Mo-W mixed oxide catalysts by 51V DNP MAS NMR is reported. It is shown that the 51V NMR signal from surface near vanadium nuclei was enhanced by a factor of ≈50 by direct polarization transfer from unpaired electrons to 51V nuclei. The dependency of the DNP enhancement of the samples on different polarizing mixtures is investigated and complemented by EPR studies. V-Mo-W mixed oxide catalysts with different stoichiometry (V2Mo8W0.5Oy, V2Mo8W1Oy, and V2Mo8W1.5Oy) are compared, and a suitable assignment of 51V signals to different phases that are present near to the catalysts surfaces is given. Finally, the applicability of DNP solid-state NMR for the characterization of V-Mo-W mixed oxide catalysts is discussed in terms of the synthesis conditions (i.e., pH-value). (Graph Presented).

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