The Bronsted acidity of three- and two-dimensional zeolites

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F19%3A00517552" target="_blank" >RIV/61388955:_____/19:00517552 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11310/19:10403394 RIV/00216275:25310/19:39914316

Výsledek na webu

<a href="http://hdl.handle.net/11104/0302886" target="_blank" >http://hdl.handle.net/11104/0302886</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.micromeso.2019.03.033" target="_blank" >10.1016/j.micromeso.2019.03.033</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The Bronsted acidity of three- and two-dimensional zeolites

Popis výsledku v původním jazyce

The zeolite activity in processes driven by Bronsted acid sites is determined by the distribution of the protons in the zeolite and strength of their interaction with the framework. This study aims to assess how much the transformation from three-dimensional (3D) bulk zeolite to its corresponding two-dimensional (2D) layered form changes the proton distribution and strength of the proton-framework interaction and thus how much it affects the zeolite Bronsted acid strength. Zeolites with three distinct topologies, MWW, PCR, and MFI, which form also layered analogues with considerably different thickness and silanol density were considered. To probe the Bronsted acidity of both 3D and 2D forms, an array of typical acidity descriptors (i.e., O-H stretching frequency, shift of O-H frequencies upon adsorption of CO probe molecule, C-O stretching frequencies and adsorption enthalpies of the CO adsorption complex) have been evaluated, employing both dispersion-corrected density functional theory and Fourier-transform infrared spectroscopy. Using these descriptors, the Bronsted acidity of 2D form is, on average, the same or just slightly lower than that of the 3D form. Transformation to layered form does affect the proton distribution and values of acidity descriptors for individual T sites, however, if all T sites are considered, the aggregate effect is almost negligible. Hence, these results suggest that a larger effect of the 3D > 2D transformation can be expected for frameworks with fewer distinct T sites.

Název v anglickém jazyce

The Bronsted acidity of three- and two-dimensional zeolites

Popis výsledku anglicky

The zeolite activity in processes driven by Bronsted acid sites is determined by the distribution of the protons in the zeolite and strength of their interaction with the framework. This study aims to assess how much the transformation from three-dimensional (3D) bulk zeolite to its corresponding two-dimensional (2D) layered form changes the proton distribution and strength of the proton-framework interaction and thus how much it affects the zeolite Bronsted acid strength. Zeolites with three distinct topologies, MWW, PCR, and MFI, which form also layered analogues with considerably different thickness and silanol density were considered. To probe the Bronsted acidity of both 3D and 2D forms, an array of typical acidity descriptors (i.e., O-H stretching frequency, shift of O-H frequencies upon adsorption of CO probe molecule, C-O stretching frequencies and adsorption enthalpies of the CO adsorption complex) have been evaluated, employing both dispersion-corrected density functional theory and Fourier-transform infrared spectroscopy. Using these descriptors, the Bronsted acidity of 2D form is, on average, the same or just slightly lower than that of the 3D form. Transformation to layered form does affect the proton distribution and values of acidity descriptors for individual T sites, however, if all T sites are considered, the aggregate effect is almost negligible. Hence, these results suggest that a larger effect of the 3D > 2D transformation can be expected for frameworks with fewer distinct T sites.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

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

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název periodika

Microporous and Mesoporous Materials

ISSN

1387-1811

e-ISSN

—

Svazek periodika

282

Číslo periodika v rámci svazku

JUL 2019

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

12

Strana od-do

121-132

Kód UT WoS článku

000471206400016

EID výsledku v databázi Scopus

2-s2.0-85063320728