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Title
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Accessibility and dispersion of vanadyl sites of vanadium silicate-1 nanoparticles deposited in SBA-15
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Author
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Abstract
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| Vanadium silicalite-1 (VS-1) nanoparticles dispersed onto the mesoporous walls of SBA-15 silica have characteristics different from those of the full-grown VS-1. In particular, the vanadium-binding site differs extensively. Here, we monitor the local environment of VO2+ with different electron paramagnetic resonance (EPR) techniques to obtain information about the heterogeneity of the vanadyl sites, the effect of a calcination/reduction cycle, and the subsequent adsorption of 13CO2 and NH3 to the vanadyl sites for both full-grown VS-1 and VS1-SBA15. Furthermore, two-cycle CO2 and NH3 adsorption experiments were performed. While the latter showed no chemisorption of CO2 at 373 K for both materials, clear evidence was found for ligation of CO2 to vanadyl in full-grown VS-1 by the detection of a strong 13C hyperfine value. This strong binding was not detected for the vanadyl centers in VS1-SBA15. Chemisorption of NH3 was detected for all samples both by two-cycle adsorption experiments and by EPR. |
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Language
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English
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Source (journal)
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The journal of physical chemistry: C : nanomaterials and interfaces. - Washington, D.C., 2007, currens
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Publication
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Washington, D.C.
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2010
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ISSN
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1932-7447
[print]
1932-7455
[online]
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Volume/pages
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114
:30
(2010)
, p. 12966-12975
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ISI
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000280360500019
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Full text (Publisher's DOI)
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