Effects of Enhanced Flexibility and Pore Size Distribution on Adsorption-Induced Deformation of Mesoporous Materials
| العنوان: | Effects of Enhanced Flexibility and Pore Size Distribution on Adsorption-Induced Deformation of Mesoporous Materials |
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| المؤلفون: | N. Georgi, Yury A. Budkov, Jörg Hofmann, Andrei L. Kolesnikov, Jens Möllmer, Juergen Adolphs, Roger Gläser |
| المصدر: | Langmuir. 34:7575-7584 |
| بيانات النشر: | American Chemical Society (ACS), 2018. |
| سنة النشر: | 2018 |
| مصطلحات موضوعية: | Materials science, Capillary condensation, Evaporation, Solvation, Thermodynamics, Rigidity (psychology), 02 engineering and technology, Surfaces and Interfaces, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Condensed Matter::Materials Science, Adsorption, Electrochemistry, General Materials Science, Density functional theory, Deformation (engineering), 0210 nano-technology, Mesoporous material, Spectroscopy |
| الوصف: | Here, we present a new model of adsorption-induced deformation of mesoporous solids. The model is based on a simplified version of local density functional theory in the framework of solvation free energy. Instead of density, which is treated as constant here, we used film thickness and pore radius as order parameters. This allows us to obtain a self-consistent system of equations describing simultaneously the processes of gas adsorption and adsorbent deformation, as well as conditions for capillary condensation and evaporation. In the limit of infinitely rigid pore walls, when the film becomes several monolayers thick, the model reduces to the well-known Derjaguin-Broekhoff-de Boer theory for pores with cylindrical geometry. We have investigated the effects of enhanced flexibility of the solid as well as the influence of pore size distribution on the adsorption/deformation process. The formulation of the theory allows to determine the average pore size and its width from the desorption branch of the strain isotherm only. The model reproduces the nonmonotonic behavior of the strain isotherm at low relative pressure. Furthermore, we discuss the effect of rigidity of the adsorbent on the pore size distribution, showing qualitatively different results of the adsorption isotherms for rigid and highly flexible materials, in particular, the shift of evaporation pressure to lower values and the absence of a limiting value of the loading at high relative pressure. We also discuss the results of the theory with respect to experimental data obtained from the literature. |
| تدمد: | 1520-5827 0743-7463 |
| DOI: | 10.1021/acs.langmuir.8b00591 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::487497715f28ec1848896c4060038f22 https://doi.org/10.1021/acs.langmuir.8b00591 |
| رقم الانضمام: | edsair.doi.dedup.....487497715f28ec1848896c4060038f22 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15205827 07437463 |
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| DOI: | 10.1021/acs.langmuir.8b00591 |