Properties of multiple Lewis acid sites in alkali metal-exchanged chabazites probed by CO adsorption

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F24%3A00585773" target="_blank" >RIV/61388963:_____/24:00585773 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216275:25310/24:39922220

Výsledek na webu

<a href="https://doi.org/10.1016/j.micromeso.2024.113152" target="_blank" >https://doi.org/10.1016/j.micromeso.2024.113152</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.micromeso.2024.113152" target="_blank" >10.1016/j.micromeso.2024.113152</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Properties of multiple Lewis acid sites in alkali metal-exchanged chabazites probed by CO adsorption

Popis výsledku v původním jazyce

Carbon monoxide adsorption on alkali-metal exchanged chabazites (M-CHA, where M = Li, Na, K) was investigated across various Si/Al ratios. The study reveals significant insights into the adsorption behavior, including the persistence of cationic preferences with decreasing Si/Al ratios and the existence of multiple-center interactions involving alkali-metal cations and CO. Results show that for high-silica M-CHA zeolites, CO adsorption is effectively described by single and dual adsorption site models, with cation preferences varying by type. In low-silica zeolites, cation positions are primarily influenced by the aluminum distribution and Coulombic interactions. However, the propensity for single-site cation positions (Si/Al→∞) is preserved to a certain degree. The most noticeable example is the small difference between SIII’ occupancies (cations in 8-membered ring windows) in Na-CHA-2 and K-CHA-2 (0.80 vs. 0.85) that strongly influences the rate of diffusion of CO in the M-CHA-2 samples. While FT-IR spectra of high-silica zeolites can be accurately described using cation site stabilities, interaction energies, and CO stretching frequencies, predicting spectra of low-silica chabazites requires a statistical approach and/or molecular dynamics simulations at the DFT level. The findings demonstrate that the dynamical behavior of adsorbates changes dramatically between different alkali metal-exchanged chabazites, highlighting the complex nature of CO adsorption at multiple Lewis acid sites.

Název v anglickém jazyce

Properties of multiple Lewis acid sites in alkali metal-exchanged chabazites probed by CO adsorption

Popis výsledku anglicky

Carbon monoxide adsorption on alkali-metal exchanged chabazites (M-CHA, where M = Li, Na, K) was investigated across various Si/Al ratios. The study reveals significant insights into the adsorption behavior, including the persistence of cationic preferences with decreasing Si/Al ratios and the existence of multiple-center interactions involving alkali-metal cations and CO. Results show that for high-silica M-CHA zeolites, CO adsorption is effectively described by single and dual adsorption site models, with cation preferences varying by type. In low-silica zeolites, cation positions are primarily influenced by the aluminum distribution and Coulombic interactions. However, the propensity for single-site cation positions (Si/Al→∞) is preserved to a certain degree. The most noticeable example is the small difference between SIII’ occupancies (cations in 8-membered ring windows) in Na-CHA-2 and K-CHA-2 (0.80 vs. 0.85) that strongly influences the rate of diffusion of CO in the M-CHA-2 samples. While FT-IR spectra of high-silica zeolites can be accurately described using cation site stabilities, interaction energies, and CO stretching frequencies, predicting spectra of low-silica chabazites requires a statistical approach and/or molecular dynamics simulations at the DFT level. The findings demonstrate that the dynamical behavior of adsorbates changes dramatically between different alkali metal-exchanged chabazites, highlighting the complex nature of CO adsorption at multiple Lewis acid sites.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

<a href="/cs/project/GA20-12735S" target="_blank" >GA20-12735S: Výzkum zeolitů s nanostrukturní architekturou: synergie experimentu a teorie</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

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

1873-3093

Svazek periodika

374

Číslo periodika v rámci svazku

June

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

7

Strana od-do

113152

Kód UT WoS článku

001237195200001

EID výsledku v databázi Scopus

2-s2.0-85192172731