Local Structure of Cationic Sites in Dehydrated Zeolites Inferred from Al-27 Magic-Angle Spinning NMR and Density Functional Theory Calculations. A Study on Li-, Na-, and K-Chabazite

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F16%3A39901499" target="_blank" >RIV/00216275:25310/16:39901499 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1021/acs.jpcc.6b04391" target="_blank" >http://dx.doi.org/10.1021/acs.jpcc.6b04391</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jpcc.6b04391" target="_blank" >10.1021/acs.jpcc.6b04391</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Local Structure of Cationic Sites in Dehydrated Zeolites Inferred from Al-27 Magic-Angle Spinning NMR and Density Functional Theory Calculations. A Study on Li-, Na-, and K-Chabazite

Popis výsledku v původním jazyce

High-resolution Al-27 magic-angle spinning (MAS) NMR spectroscopy of dehydrated M-forms (M = Li, Na, and K) of chabazite in tandem with density functional theory calculations are employed to study the quadrupolar interaction of Al-27 nuclei in dehydrated zeolites and to understand the corresponding high-resolution Al-27 MAS NMR spectra. We show that the broadening of the Al-27 NMR signal in dehydrated zeolites occurs predominantly because of the deformation of the local structure of AlO4- tetrahedra caused by the binding of M+ to the zeolite framework. This deformation increases with the decreasing diameter of the cations from K+ to Li+. The influence of water in hydrated zeolites is limited only to prevent a strong coordination of the M+ cation to O atoms of the AlO4- tetrahedron, but there is no "averaging" effect concerning the local electrostatic field due to molecular motion of water molecules. Our results show that the Al-27 NMR parameters in dehydrated zeolites can be calculated accurately enough to allow the description of the local structure of AlO4- tetrahedra in dehydrated zeolites and to infer the local structure of the sites accommodating the extraframework M+ cations.

Název v anglickém jazyce

Local Structure of Cationic Sites in Dehydrated Zeolites Inferred from Al-27 Magic-Angle Spinning NMR and Density Functional Theory Calculations. A Study on Li-, Na-, and K-Chabazite

Popis výsledku anglicky

High-resolution Al-27 magic-angle spinning (MAS) NMR spectroscopy of dehydrated M-forms (M = Li, Na, and K) of chabazite in tandem with density functional theory calculations are employed to study the quadrupolar interaction of Al-27 nuclei in dehydrated zeolites and to understand the corresponding high-resolution Al-27 MAS NMR spectra. We show that the broadening of the Al-27 NMR signal in dehydrated zeolites occurs predominantly because of the deformation of the local structure of AlO4- tetrahedra caused by the binding of M+ to the zeolite framework. This deformation increases with the decreasing diameter of the cations from K+ to Li+. The influence of water in hydrated zeolites is limited only to prevent a strong coordination of the M+ cation to O atoms of the AlO4- tetrahedron, but there is no "averaging" effect concerning the local electrostatic field due to molecular motion of water molecules. Our results show that the Al-27 NMR parameters in dehydrated zeolites can be calculated accurately enough to allow the description of the local structure of AlO4- tetrahedra in dehydrated zeolites and to infer the local structure of the sites accommodating the extraframework M+ cations.

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

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

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

—

Svazek periodika

120

Číslo periodika v rámci svazku

26

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

10

Strana od-do

14216-14225

Kód UT WoS článku

000379457000039

EID výsledku v databázi Scopus

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