Structural thermodynamics of adsorption on UiO-66 Metal–organic frameworks: A unified thermodynamic framework for surface energetics, Lewis acid–base interactions, and polar surface energy
- 1Faculty of Science and Engineering, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands; Institut de Science des Matériaux de Mulhouse, Université de Haute-Alsace, CNRS, IS2M UMR 7361, F-68100 Mulhouse, France; Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences, Lebanese University, Beirut P.O. Box 6573/14, Lebanon
Abstract
A unified thermodynamic framework is developed for the structural and energetic characterization of UiO-66 metal–organic frameworks using inverse gas chromatography at infinite dilution. Pristine UiO-66 and amino-, formic acid-, and acetic acid-functionalized derivatives were investigated over 313.15–383.15 K. The standard Gibbs free energy of adsorption is expressed as a function of temperature and specific surface area, demonstrating the intrinsic dependence of adsorption thermodynamics on adsorbent structure. This leads to the generalized relation, Δ G a 0 ( T , S ) = Δ H a 0 ( S ) − T Δ S a 0 ( S ) , in which adsorption enthalpy and entropy become continuous structural functions rather than invariant quantities across a porous-material family. The effective molecular surface area of adsorbed solvents also depends on temperature and surface structure, revealing changes in molecular organization within the adsorption layer. Lewis acid–base interactions were analyzed by applying the Hamieh five-parameter thermodynamic model independently to adsorption enthalpy and entropy. Statistical analysis confirms the superiority of nonlinear higher-order models over conventional linear approaches and reveals correlations among acidic, basic, amphoteric, and cooperative interaction parameters. Functionalization markedly modifies Lewis acidity, basicity, and polar surface energy while only weakly affecting London dispersive interactions. A new methodology is further introduced to determine the polar surface energy of adsorbed solvent molecules, demonstrating that the adsorbed phase possesses thermodynamic surface properties governed by solvent–framework interactions. Overall, the proposed framework unifies adsorption thermodynamics, molecular organization, Lewis acid–base interactions, and surface energetics, providing a general methodology for characterizing and rationally designing advanced porous materials.
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BibTeX
@article{hamieh2026structural,
title = {{Structural thermodynamics of adsorption on UiO-66 Metal–organic frameworks: A unified thermodynamic framework for surface energetics, Lewis acid–base interactions, and polar surface energy}},
author = {Tayssir Hamieh},
journal = {Applied Surface Science Advances},
year = {2026},
month = oct,
doi = {10.1016/j.apsadv.2026.101056},
url = {https://doi.org/10.1016/j.apsadv.2026.101056},
note = {CC BY},
}
RIS
TY - JOUR
TI - Structural thermodynamics of adsorption on UiO-66 Metal–organic frameworks: A unified thermodynamic framework for surface energetics, Lewis acid–base interactions, and polar surface energy
AU - Tayssir Hamieh
PY - 2026
DA - 2026/10/24
JO - Applied Surface Science Advances
DO - 10.1016/j.apsadv.2026.101056
UR - https://doi.org/10.1016/j.apsadv.2026.101056
AB - A unified thermodynamic framework is developed for the structural and energetic characterization of UiO-66 metal–organic frameworks using inverse gas chromatography at infinite dilution. Pristine UiO-66 and amino-, formic acid-, and acetic acid-functionalized derivatives were investigated over 313.15–383.15 K. The standard Gibbs free energy of adsorption is expressed as a function of temperature and specific surface area, demonstrating the intrinsic dependence of adsorption thermodynamics on adsorbent structure. This leads to the generalized relation, Δ G a 0 ( T , S ) = Δ H a 0 ( S ) − T Δ S a 0 ( S ) , in which adsorption enthalpy and entropy become continuous structural functions rather than invariant quantities across a porous-material family. The effective molecular surface area of adsorbed solvents also depends on temperature and surface structure, revealing changes in molecular organization within the adsorption layer. Lewis acid–base interactions were analyzed by applying the Hamieh five-parameter thermodynamic model independently to adsorption enthalpy and entropy. Statistical analysis confirms the superiority of nonlinear higher-order models over conventional linear approaches and reveals correlations among acidic, basic, amphoteric, and cooperative interaction parameters. Functionalization markedly modifies Lewis acidity, basicity, and polar surface energy while only weakly affecting London dispersive interactions. A new methodology is further introduced to determine the polar surface energy of adsorbed solvent molecules, demonstrating that the adsorbed phase possesses thermodynamic surface properties governed by solvent–framework interactions. Overall, the proposed framework unifies adsorption thermodynamics, molecular organization, Lewis acid–base interactions, and surface energetics, providing a general methodology for characterizing and rationally designing advanced porous materials.
SN - 2666-5239
ER -