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Confinement effects and acid strength in zeolites

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Grifoni, Emanuele, Piccini, GiovanniMaria, Lercher, Johannes A., Glezakou, Vassiliki-Alexandra, Rousseau, Roger, Parrinello, Michele·2021·Nature Communications
DOI 10.1038/s41467-021-22936-0PMC PMC8113345

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Abstract

Chemical reactivity and sorption in zeolites are coupled to confinement and-to a lesser extent-to the acid strength of Brønsted acid sites (BAS). In presence of water the zeolite Brønsted acid sites eventually convert into hydronium ions. The gradual transition from zeolite Brønsted acid sites to hydronium ions in zeolites of varying pore size is examined by ab initio molecular dynamics combined with enhanced sampling based on Well-Tempered Metadynamics and a recently developed set of collective variables. While at low water content (1-2 water/BAS) the acidic protons prefer to be shared between zeolites and water, higher water contents (n > 2) invariably lead to solvation of the protons within a localized water cluster adjacent to the BAS. At low water loadings the standard free energy of the formed complexes is dominated by enthalpy and is associated with the acid strength of the BAS and the space around the site. Conversely, the entropy increases linearly with the concentration of waters in the pores, favors proton solvation and is independent of the pore size/shape.

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  • Proper mechanistic understanding of BAS-water-zeolite interactions is still lacking, limited to either static calculations at ultra-high vacuum conditions or exploratory (ab initio) dynamical simulations of narrow scope.

    “As a result, the proper mechanistic understanding of BAS-water-zeolite interactions is still lacking, limited to either static calculations at ultra-high vacuum conditions13,14 or exploratory (ab initio) dynamical simulations of narrow scope15–18.”

    From A reactive neural network framework for water-loaded acidic zeolites (2024) · cites this paper as [17]

    The Introduction (page unavailable) describes full ab initio metadynamics across four zeolite frameworks and multiple water loadings, yielding thermodynamic and mechanistic information at atomistic detail—not a dynamical study of narrow scope. The Results and discussion report general findings about BAS solvation, contrary to the claim that mechanistic understanding remains limited to such studies. (LLM, conf=0.85)

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  • Both the degree of deprotonation and the distance of the proton from the BAS as a function of water loading are in very good agreement with biased AIMD simulations of Grifoni et al. for protonic FAU zeolite.

    “Importantly, both the degree of deprotonation and the distance of the proton from the BAS as a function of water loading are in very good agreement with the biased AIMD simulations of Grifoni et al. for protonic FAU zeolite17.”

    From A reactive neural network framework for water-loaded acidic zeolites (2024) · cites this paper as [17]

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Authors
Grifoni, E., Piccini, G., Lercher, J. A., Glezakou, V.-A., Rousseau, R., & Parrinello, M.
Affiliations
  • Scuola Normale Superiore (IT)
  • Pacific Northwest National Laboratory (US)
  • Italian Institute of Technology (IT)
Corresponding author
  • Glezakou, Vassiliki-Alexandra
  • Rousseau, Roger
  • Parrinello, Michele
ORCID
Venue
Nature Communications
Publisher
Springer Science and Business Media LLC
Published
2021-05-11
Volume
12
Issue
1
Pages
2630-2630
ISSN
2041-1723 (ISSN-L)
DOI
10.1038/s41467-021-22936-0
PMC
PMC8113345
OpenAlex
W3161986486
Cited by
203
References
2
Citations by year
2026: 38 · 2025: 44 · 2024: 44 · 2023: 39 · 2022: 26 · 2021: 12
FWCI
9.78
Type
journal article
Language
en
Open access
Licence
Locations
  • Nature Communications (publishedVersion, cc-by)
  • Research Square (acceptedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (submittedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • IRIS UNIMORE (University of Modena and Reggio Emilia) (submittedVersion, cc-by)
  • Repository for Publications and Research Data (ETH Zurich) (submittedVersion, cc-by)
  • ETH Zürich Research Collection (cc-by)
Funders
  • U.S. Department of Energy (DE-AC05–76RL01830, -AC02-05CH11231, Contract No. DE-AC02-05-CH11231, 76RL01830, AC05-76RL01830, DE-AC05?, 05CH11231, Contract DE-AC05-76RL01830, No. DE-AC02-05-CH11231, DE AC02 05CH11231, DE-AC02-)
  • Battelle (AC05-76RL01830, DE- AC05-76RL01830, DE-AC05)
  • National Energy Research Scientific Computing Center (DE–AC02–05CH11231, 05CH11231, AC02-05CH11231, Contract No. DE-AC02-05CH11231)
  • European Commission (ERC-2014-AdG, ERC‐2014‐AdG‐670227/VARMET, DE-AC02-05CH11231, 670227, ERC-2014)
  • Centro Svizzero di Calcolo Scientifico (DE-AC02-05CH11231)
  • National Supercomputing Centre Singapore
  • Office of Science
  • Basic Energy Sciences (DE-AC02, Contract No. DE-AC02-05-CH11231, DE-AC05-76RL01830, 05CH11231, DE-AC02-05CH11231., No. DE-AC02-05-CH11231, AC02–05CH11231)
  • Lawrence Berkeley National Laboratory (AC02‐05CH11231, DE-AC02-05CH11231, No. DE-AC02-05CH11231, DE-AC05-76RL01830, Contract No. DE-AC02-05CH11231, 05CH11231)
  • Pacific Northwest National Laboratory (DEAC0576RL01830, 76RL01830, DE-AC02-05CH11231, AC05-76RL01830)
Topics
  • Physical Sciences › Chemistry › Inorganic Chemistry › Zeolite Catalysis and Synthesis
  • Physical Sciences › Environmental Science › Waste Management and Disposal › Chemical Synthesis and Characterization
  • Physical Sciences › Chemistry › Inorganic Chemistry › Metal-Organic Frameworks: Synthesis and Applications
Keywords
zeolites, Brønsted acid sites, acid strength, confinement effects, hydronium ion, proton solvation, water loading, proton hydration, pore size, collective variables, well-tempered metadynamics, enthalpy-entropy compensation, acid-base chemistry

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