Chemically accurate predictions for water adsorption on Brønsted sites of zeolite H-MFI

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F24%3A10490499" target="_blank" >RIV/00216208:11310/24:10490499 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=_KPCL8~BBB" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=_KPCL8~BBB</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d4cp02851a" target="_blank" >10.1039/d4cp02851a</a>

Result language

angličtina

Original language name

Chemically accurate predictions for water adsorption on Brønsted sites of zeolite H-MFI

Original language description

We investigate the adsorption of water molecules in the zeolite H-MFI at isolated Bronsted acid sites (BAS) for loadings of 1, 2, and 3 H2O/BAS. We consider two approaches to the O3Al-O(H)-Si sites: the Bronsted-type approach of H2O to the acidic proton and the Lewis-type approach to the aluminium atom of the AlO4 tetrahedron. From the twelve crystallographically inequivalent framework sites for Al, a representative set of six active site positions is chosen. For them, we calculate CCSD(T)-quality adsorption energies at MP2-quality adsorption structures for different approaches, 48 in total. TheBronsted-type approach is favoured for most cases but the Lewis-type approach has similar stability for some framework positions. We predict heats of adsorption per molecule ranging from 60 to 76, 56 to 65, and 56 to 64 kJ mol(-1) for loadings of 1, 2, and 3 H2O/BAS, respectively. For 1 H2O/BAS, the experimental result (70 kJ mol(-1)) falls into the range of our predictions, whereas for 2 and 3 H2O/BAS, the measured adsorption heats per molecule (74 and 70 kJ mol(-1), respectively) are larger than our predictions. For 2 H2O/BAS, the ion-pair structure generated by proton transfer to the water dimer competes with the neutral adsorption complex. The DFT adsorption energies (PBE+D2) deviate significantly from the CCSD(T)-quality reference energies, by up to 25 kJ mol(-1) for 1 H2O/BAS, 25 kJ mol(-1) per H2O for 2 H2O/BAS, and 18 kJ mol(-1) per H2O for 3 H2O/BAS. Specifically, PBE+D2 overstabilises the ion-pair structure, i.e. in many cases the PBE+D2 error is much larger for ionic than for neutral adsorption structures. Accurate predictions of the heat of water adsorption and the protonation state requires passing from density functional theory (PBE+D) to wavefunction methods (MP2).

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10403 - Physical chemistry

Project

<a href="/en/project/EF15_003%2F0000417" target="_blank" >EF15_003/0000417: Center for Advanced Materials: Design, Synthesis, and Applications</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

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

Name of the periodical

Physical Chemistry Chemical Physics

ISSN

1463-9076

e-ISSN

1463-9084

Volume of the periodical

26

Issue of the periodical within the volume

36

Country of publishing house

GB - UNITED KINGDOM

Number of pages

12

Pages from-to

23588-23599

UT code for WoS article

001304182700001

EID of the result in the Scopus database

2-s2.0-85203154680