From single-site tantalum complexes to nanoparticles of TaxNy and TaOxNy supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopy

Handle URI:
http://hdl.handle.net/10754/625337
Title:
From single-site tantalum complexes to nanoparticles of TaxNy and TaOxNy supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopy
Authors:
Mohandas, Janet Chakkamadathil ( 0000-0001-9088-4142 ) ; Abou-Hamad, Edy; Callens, Emmanuel ( 0000-0001-9177-0091 ) ; Samantaray, Manoja ( 0000-0001-8131-0606 ) ; Gajan, David; Gurinov, Andrei ( 0000-0002-9488-3064 ) ; Ma, Tao ( 0000-0002-0579-8045 ) ; Ould-Chikh, Samy ( 0000-0002-3486-0944 ) ; Hoffman, Adam S.; Gates, Bruce C. ( 0000-0003-0274-4882 ) ; Basset, Jean-Marie ( 0000-0003-3166-8882 )
Abstract:
Air-stable catalysts consisting of tantalum nitride nanoparticles represented as a mixture of TaxNy and TaOxNy with diameters in the range of 0.5 to 3 nm supported on highly dehydroxylated silica were synthesized from TaMe5 (Me = methyl) and dimeric Ta-2(OMe)(10) with guidance by the principles of surface organometallic chemistry (SOMC). Characterization of the supported precursors and the supported nanoparticles formed from them was carried out by IR, NMR, UV-Vis, extended X-ray absorption fine structure, and X-ray photoelectron spectroscopies complemented with XRD and high-resolution TEM, with dynamic nuclear polarization surface enhanced NMR spectroscopy being especially helpful by providing enhanced intensities of the signals of H-1, C-13, Si-29, and N-15 at their natural abundances. The characterization data provide details of the synthesis chemistry, including evidence of (a) O-2 insertion into Ta-CH3 species on the support and (b) a binuclear to mononuclear transformation of species formed from Ta-2(OMe)(10) on the support. A catalytic test reaction, cyclooctene epoxidation, was used to probe the supported nanoparticles, with 30% H2O2 serving as the oxidant. The catalysts gave selectivities up to 98% for the epoxide at conversions as high as 99% with a 3.4 wt% loading of Ta present as TaxNy/TaOxNy.
KAUST Department:
KAUST Catalysis Center (KCC)
Citation:
Mohandas JC, Abou-Hamad E, Callens E, Samantaray MK, Gajan D, et al. (2017) From single-site tantalum complexes to nanoparticles of TaxNy and TaOxNy supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopy. Chem Sci 8: 5650–5661. Available: http://dx.doi.org/10.1039/c7sc01365e.
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Chem. Sci.
Issue Date:
8-Jun-2017
DOI:
10.1039/c7sc01365e
Type:
Article
ISSN:
2041-6520; 2041-6539
Sponsors:
We gratefully acknowledge the financial support provided by the King Abdullah University of Science and Technology (KAUST). We thank Dr Kun Li, Dr Nejib Hedili, and Dr Abdul-Hamid Emwas of the KAUST core labs for HRTEM, XPS, and NMR measurements, respectively, and Prof. Kazuhiro Takanabe for help with the ammonia treatments. We acknowledge Prof. Lyndon Emsley, EPFL, Switzerland, for helpful suggestions. We acknowledge beam time at beamline 4-1 of the Stanford Synchrotron Radiation Lightsource supported by the U.S. DOE Division of Materials Science under Contract No. DE-AC02-76SF00515.
Additional Links:
http://pubs.rsc.org/en/Content/ArticleLanding/2017/SC/C7SC01365E#!divAbstract
Appears in Collections:
Articles; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorMohandas, Janet Chakkamadathilen
dc.contributor.authorAbou-Hamad, Edyen
dc.contributor.authorCallens, Emmanuelen
dc.contributor.authorSamantaray, Manojaen
dc.contributor.authorGajan, Daviden
dc.contributor.authorGurinov, Andreien
dc.contributor.authorMa, Taoen
dc.contributor.authorOuld-Chikh, Samyen
dc.contributor.authorHoffman, Adam S.en
dc.contributor.authorGates, Bruce C.en
dc.contributor.authorBasset, Jean-Marieen
dc.date.accessioned2017-08-14T06:41:38Z-
dc.date.available2017-08-14T06:41:38Z-
dc.date.issued2017-06-08en
dc.identifier.citationMohandas JC, Abou-Hamad E, Callens E, Samantaray MK, Gajan D, et al. (2017) From single-site tantalum complexes to nanoparticles of TaxNy and TaOxNy supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopy. Chem Sci 8: 5650–5661. Available: http://dx.doi.org/10.1039/c7sc01365e.en
dc.identifier.issn2041-6520en
dc.identifier.issn2041-6539en
dc.identifier.doi10.1039/c7sc01365een
dc.identifier.urihttp://hdl.handle.net/10754/625337-
dc.description.abstractAir-stable catalysts consisting of tantalum nitride nanoparticles represented as a mixture of TaxNy and TaOxNy with diameters in the range of 0.5 to 3 nm supported on highly dehydroxylated silica were synthesized from TaMe5 (Me = methyl) and dimeric Ta-2(OMe)(10) with guidance by the principles of surface organometallic chemistry (SOMC). Characterization of the supported precursors and the supported nanoparticles formed from them was carried out by IR, NMR, UV-Vis, extended X-ray absorption fine structure, and X-ray photoelectron spectroscopies complemented with XRD and high-resolution TEM, with dynamic nuclear polarization surface enhanced NMR spectroscopy being especially helpful by providing enhanced intensities of the signals of H-1, C-13, Si-29, and N-15 at their natural abundances. The characterization data provide details of the synthesis chemistry, including evidence of (a) O-2 insertion into Ta-CH3 species on the support and (b) a binuclear to mononuclear transformation of species formed from Ta-2(OMe)(10) on the support. A catalytic test reaction, cyclooctene epoxidation, was used to probe the supported nanoparticles, with 30% H2O2 serving as the oxidant. The catalysts gave selectivities up to 98% for the epoxide at conversions as high as 99% with a 3.4 wt% loading of Ta present as TaxNy/TaOxNy.en
dc.description.sponsorshipWe gratefully acknowledge the financial support provided by the King Abdullah University of Science and Technology (KAUST). We thank Dr Kun Li, Dr Nejib Hedili, and Dr Abdul-Hamid Emwas of the KAUST core labs for HRTEM, XPS, and NMR measurements, respectively, and Prof. Kazuhiro Takanabe for help with the ammonia treatments. We acknowledge Prof. Lyndon Emsley, EPFL, Switzerland, for helpful suggestions. We acknowledge beam time at beamline 4-1 of the Stanford Synchrotron Radiation Lightsource supported by the U.S. DOE Division of Materials Science under Contract No. DE-AC02-76SF00515.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.relation.urlhttp://pubs.rsc.org/en/Content/ArticleLanding/2017/SC/C7SC01365E#!divAbstracten
dc.rightsThis article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.en
dc.rights.urihttp://creativecommons.org/licenses/by-nc/3.0/en
dc.titleFrom single-site tantalum complexes to nanoparticles of TaxNy and TaOxNy supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopyen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.identifier.journalChem. Sci.en
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionInstitut de Sciences Analytiques (CNRS/ENS-Lyon/UCB-Lyon 1), Université de Lyon, Centre de RMN À Très Hauts Champs, Villeurbanne, 69100, , , , Franceen
dc.contributor.institutionDepartment of Chemical Engineering, University of California, Davis, CA, 95616, , United Statesen
kaust.authorMohandas, Janet Chakkamadathilen
kaust.authorAbou-Hamad, Edyen
kaust.authorCallens, Emmanuelen
kaust.authorSamantaray, Manojaen
kaust.authorGurinov, Andreien
kaust.authorOuld-Chikh, Samyen
kaust.authorBasset, Jean-Marieen
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.