Multiple equilibria description of type H1 hysteresis in gas sorption isotherms of mesoporous materials

Calzaferri, Gion; Gallagher, Samuel H.; Lustenberger, Simon; Walther, Fabian; Brühwiler, Dominik

doi:10.1016/j.matchemphys.2022.127121

Please use this identifier to cite or link to this item: https://doi.org/10.21256/zhaw-26572

Publication type:	Article in scientific journal
Type of review:	Peer review (publication)
Title:	Multiple equilibria description of type H1 hysteresis in gas sorption isotherms of mesoporous materials
Authors:	Calzaferri, Gion Gallagher, Samuel H. Lustenberger, Simon Walther, Fabian Brühwiler, Dominik
et. al:	No
DOI:	10.1016/j.matchemphys.2022.127121 10.21256/zhaw-26572
Published in:	Materials Chemistry and Physics
Volume(Issue):	296
Issue:	127121
Issue Date:	2023
Publisher / Ed. Institution:	Elsevier
ISSN:	0254-0584
Language:	English
Subject (DDC):	540: Chemistry
Abstract:	We report argon adsorption/desorption isotherms of MCM-41 and of SBA-15. The shape of all hysteresis loops we have observed corresponds to type H1. The data have been analyzed quantitatively using the multiple equilibria description and applying the notion of metastable thermodynamic equilibrium. It is remarkable and important that for both mesoporous materials the desorption process can be understood according to this description but with a corresponding equilibrium constant. This procedure therefore allows determining the thermodynamic values for the enthalpy and the free enthalpy of cavity desorption and thus to obtain information not available so far. We observed that the MCM-41 adsorption isotherms show first an increase with the characteristic Langmuir shape, followed by the almost instantaneous filling of cavities that ends as soon as all cavities are completely filled. The SBA-15 isotherms show a characteristic Langmuir shape at low relative pressure. The pressure slightly below the inflection point at prel, infl = 0.312 marks the beginning of the growth of a second layer, before an almost instantaneous filling of cavities takes place. It is interesting to observe that the values of the enthalpy and the free enthalpy for cavity filling and cavity desorption differ by about 0.1 kJ/mol for both, MCM-41 and SBA-15. This means that the driving force for developing a hysteresis is small. The hysteresis loop is therefore driven by delicate changes occurring within the cavities, partially or completely filled by the adsorbate. The monolayer coverage and monolayer desorption processes are decoupled from the cavity filling and cavity emptying processes. Knowing thermodynamic parameters for the hysteresis loop ultimately helps to better characterize and understand the experimental observations.
URI:	https://digitalcollection.zhaw.ch/handle/11475/26572
Fulltext version:	Published version
License (according to publishing contract):	CC BY 4.0: Attribution 4.0 International
Departement:	Life Sciences and Facility Management
Organisational Unit:	Institute of Chemistry and Biotechnology (ICBT)
Appears in collections:	Publikationen Life Sciences und Facility Management

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Calzaferri, G., Gallagher, S. H., Lustenberger, S., Walther, F., & Brühwiler, D. (2023). Multiple equilibria description of type H1 hysteresis in gas sorption isotherms of mesoporous materials. Materials Chemistry and Physics, 296(127121). https://doi.org/10.1016/j.matchemphys.2022.127121

Calzaferri, G. et al. (2023) ‘Multiple equilibria description of type H1 hysteresis in gas sorption isotherms of mesoporous materials’, Materials Chemistry and Physics, 296(127121). Available at: https://doi.org/10.1016/j.matchemphys.2022.127121.

G. Calzaferri, S. H. Gallagher, S. Lustenberger, F. Walther, and D. Brühwiler, “Multiple equilibria description of type H1 hysteresis in gas sorption isotherms of mesoporous materials,” Materials Chemistry and Physics, vol. 296, no. 127121, 2023, doi: 10.1016/j.matchemphys.2022.127121.

CALZAFERRI, Gion, Samuel H. GALLAGHER, Simon LUSTENBERGER, Fabian WALTHER und Dominik BRÜHWILER, 2023. Multiple equilibria description of type H1 hysteresis in gas sorption isotherms of mesoporous materials. Materials Chemistry and Physics. 2023. Bd. 296, Nr. 127121. DOI 10.1016/j.matchemphys.2022.127121

Calzaferri, Gion, Samuel H. Gallagher, Simon Lustenberger, Fabian Walther, and Dominik Brühwiler. 2023. “Multiple Equilibria Description of Type H1 Hysteresis in Gas Sorption Isotherms of Mesoporous Materials.” Materials Chemistry and Physics 296 (127121). https://doi.org/10.1016/j.matchemphys.2022.127121.

Calzaferri, Gion, et al. “Multiple Equilibria Description of Type H1 Hysteresis in Gas Sorption Isotherms of Mesoporous Materials.” Materials Chemistry and Physics, vol. 296, no. 127121, 2023, https://doi.org/10.1016/j.matchemphys.2022.127121.