Effect of Al/Si Substitutions and Silanol Nests on the Local Geometry of Si and Al Framework Sites in Silicone-Rich Zeolites: A Combined High Resolution Al-27 and Si-29 NMR and Density Functional Theory/Molecular Mechanics Study

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F09%3A00336493" target="_blank" >RIV/61388955:_____/09:00336493 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61389013:_____/09:00336493

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Effect of Al/Si Substitutions and Silanol Nests on the Local Geometry of Si and Al Framework Sites in Silicone-Rich Zeolites: A Combined High Resolution Al-27 and Si-29 NMR and Density Functional Theory/Molecular Mechanics Study

Popis výsledku v původním jazyce

We employed Si-29 and Al-27 (3Q) magic-angle spinning (MAS) NMR spectroscopy and density functional theory/molecular mechanics (DFT/MM) calculations to investigate the effect of Al/Si substitutions and the presence of silanol nests on the Si-29 and Al-27NMR parameters as well as the local geometry Of SiO4 and AlO4- tetrahedra of the nearest and next-nearest neighboring Si and Al atoms. The silicon-rich zeolite of the chabazite structure (Si/Al 38) was chosen for this study as a representative model ofsilicon-rich zeolites since it exhibits a low number of distinguishable T sites. Our computational results show the following: (1) Al atoms can occupy three different crystallographic T sites in the framework of chabazite (Si/Al 38). This result is in agreement with two observed Al-27 NMR resonances. (II) An Al/Si substitution causes a downshift of the Si-29 chemical shift of the nearest neighboring Si atoms (Al-O-Si) by 4-11 ppm...

Název v anglickém jazyce

Effect of Al/Si Substitutions and Silanol Nests on the Local Geometry of Si and Al Framework Sites in Silicone-Rich Zeolites: A Combined High Resolution Al-27 and Si-29 NMR and Density Functional Theory/Molecular Mechanics Study

Popis výsledku anglicky

We employed Si-29 and Al-27 (3Q) magic-angle spinning (MAS) NMR spectroscopy and density functional theory/molecular mechanics (DFT/MM) calculations to investigate the effect of Al/Si substitutions and the presence of silanol nests on the Si-29 and Al-27NMR parameters as well as the local geometry Of SiO4 and AlO4- tetrahedra of the nearest and next-nearest neighboring Si and Al atoms. The silicon-rich zeolite of the chabazite structure (Si/Al 38) was chosen for this study as a representative model ofsilicon-rich zeolites since it exhibits a low number of distinguishable T sites. Our computational results show the following: (1) Al atoms can occupy three different crystallographic T sites in the framework of chabazite (Si/Al 38). This result is in agreement with two observed Al-27 NMR resonances. (II) An Al/Si substitution causes a downshift of the Si-29 chemical shift of the nearest neighboring Si atoms (Al-O-Si) by 4-11 ppm...

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CF - Fyzikální chemie a teoretická chemie

OECD FORD obor

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Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>Z - Vyzkumny zamer (s odkazem do CEZ)

Rok uplatnění

2009

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Physical Chemistry C

ISSN

1932-7447

e-ISSN

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Svazek periodika

113

Číslo periodika v rámci svazku

32

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

13

Strana od-do

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Kód UT WoS článku

000268661300059

EID výsledku v databázi Scopus

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