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Laird M, Herrmann N, Carcel C, Trens P, Oliviero E, Toquer G, Le Parc R, Bantignies JL, Bartlett JR, Wong Chi Man M. Mesoporous organosilicas with thiol functionalised pores: multifunctional dendrimers as sacrificial building block and template. NANOSCALE 2022; 14:15617-15634. [PMID: 36070553 DOI: 10.1039/d2nr03097g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The synthesis of multifunctional poly(amidoamine) (PAMAM)-based dendrimers containing a cleavable disulfide linker within each arm of the dendrimer, together with condensable triethoxysilyl groups on the periphery of the dendrimer, is described. The dendrimers were mixed with 1,4-bis(triethoxysilyl)benzene and subsequently transformed into silsesquioxane gels or periodic mesoporous organosilicas (PMOs) to generate materials with dendrimers covalently embedded within the interior of the silsesquioxane networks. Subsequent treatment of the gels with dithiothreitol enabled the core of the dendrimers to be selectively cleaved at the disulfide site, thus generating thiol functions localised within the pores. The effect of different dendrimer generations on the reactivity of the pendant thiol functions was probed by impregnation with gold salts, which were reduced to obtain gold nanoparticles within the pore networks of the gels and PMOs. The gels yielded polydisperse gold nanoparticles (2 to 70 nm) with dimensions modulated by the generation of the dendrimer, together with well-defined gold/thiolate clusters with Au⋯S distances of 2.3 Å. Such clusters were also observed in the PMO system, together with monodispersed gold nanoparticles with diameters comparable to that of the organised pores in the PMO. The role of surface functionalisation in controlling the formation of gold clusters and/or nanoparticles is discussed.
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Affiliation(s)
- Mathilde Laird
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | | | - Carole Carcel
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | - Philippe Trens
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | | | | | - Rozenn Le Parc
- Laboratoire Charles Coulomb (L2C), CNRS-Univ. Montpellier, Montpellier, France
| | | | - John R Bartlett
- Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia.
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2
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Characterization of mesoporous region by the scanning of the hysteresis loop in adsorption–desorption isotherms. ADSORPTION 2021. [DOI: 10.1007/s10450-021-00342-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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3
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Boudjema L, Long J, Petitjean H, Larionova J, Guari Y, Trens P, Salles F. Adsorption of volatile organic compounds by ZIF-8, Cu-BTC and a Prussian blue analogue: A comparative study. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2019.119316] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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4
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Mamontova E, Trens P, Salles F, Fraisse B, Gimello O, Guari Y, Larionova J, Long J. Enantioselective separation under humid conditions by chiral Hofmann clathrates: new opportunities for vintage materials. Inorg Chem Front 2019. [DOI: 10.1039/c9qi00837c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Chiral Hofmann clathrates for enantioselective adsorption/separation.
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Affiliation(s)
- Ekaterina Mamontova
- Institut Charles Gerhardt Montpellier
- UMR 5253
- Ingénierie Moléculaire et Nano-Objets
- Université de Montpellier
- CNRS
| | - Philippe Trens
- Institut Charles Gerhardt
- UMR 5253
- Equipe Matériaux Avancés pour la Catalyse et la Santé
- ENSCM
- CNRS
| | - Fabrice Salles
- Institut Charles Gerhardt Montpellier
- UMR 5253
- Agrégats
- Interfaces et Matériaux pour l'Energie Université de Montpellier
- CNRS
| | - Bernard Fraisse
- Institut Charles Gerhardt Montpellier
- UMR 5253
- Agrégats
- Interfaces et Matériaux pour l'Energie Université de Montpellier
- CNRS
| | - Olinda Gimello
- Institut Charles Gerhardt
- UMR 5253
- Equipe Matériaux Avancés pour la Catalyse et la Santé
- ENSCM
- CNRS
| | - Yannick Guari
- Institut Charles Gerhardt Montpellier
- UMR 5253
- Ingénierie Moléculaire et Nano-Objets
- Université de Montpellier
- CNRS
| | - Joulia Larionova
- Institut Charles Gerhardt Montpellier
- UMR 5253
- Ingénierie Moléculaire et Nano-Objets
- Université de Montpellier
- CNRS
| | - Jérôme Long
- Institut Charles Gerhardt Montpellier
- UMR 5253
- Ingénierie Moléculaire et Nano-Objets
- Université de Montpellier
- CNRS
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5
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Tan SP, Piri M. Heat of capillary condensation in nanopores: new insights from the equation of state. Phys Chem Chem Phys 2017; 19:5540-5549. [DOI: 10.1039/c6cp07814a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For the first time, the heat of capillary condensation in nanopores is analyzed as it varies with temperature and pore size.
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Affiliation(s)
- Sugata P. Tan
- Department of Petroleum Engineering
- University of Wyoming
- Laramie
- USA
| | - Mohammad Piri
- Department of Petroleum Engineering
- University of Wyoming
- Laramie
- USA
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Chan DY, Sega AG, Lee JY, Gao T, Cunin F, Renzo FD, Sailor MJ. Optical detection of C 2 hydrocarbons ethane, ethylene, and acetylene with a photonic crystal made from carbonized porous silicon. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.07.069] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Coasne B, Galarneau A, Pellenq RJM, Di Renzo F. Adsorption, intrusion and freezing in porous silica: the view from the nanoscale. Chem Soc Rev 2013; 42:4141-71. [PMID: 23348418 DOI: 10.1039/c2cs35384a] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Benoit Coasne
- Institut Charles Gerhardt Montpellier, CNRS (UMR 5253), University Montpellier 2, ENSCM, 8 rue de l'Ecole Normale, 34296 Montpellier, France.
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Wang L, Shylesh S, Dehe D, Philippi T, Dörr G, Seifert A, Zhou Z, Hartmann M, Klupp Taylor RN, Jia M, Ernst S, Thiel WR. Covalent Immobilization of Imidazolium Cations Inside a Silica Support: Palladium‐Catalyzed Olefin Hydrogenation. ChemCatChem 2012. [DOI: 10.1002/cctc.201100329] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Lei Wang
- Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin‐Schrödinger‐Str. Geb. 54, 67661 Kaiserslautern (Germany), Fax: (+49) 631‐2054676
- Key Laboratory of Surface and Interface Chemistry of Jilin Province, College of Chemistry, Jilin University, Changchun, 130012 (China)
| | - Sankaranarayanapillai Shylesh
- Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin‐Schrödinger‐Str. Geb. 54, 67661 Kaiserslautern (Germany), Fax: (+49) 631‐2054676
| | - Daniel Dehe
- Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin‐Schrödinger‐Str. Geb. 54, 67661 Kaiserslautern (Germany), Fax: (+49) 631‐2054676
| | - Thomas Philippi
- Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin‐Schrödinger‐Str. Geb. 54, 67661 Kaiserslautern (Germany), Fax: (+49) 631‐2054676
| | - Gunder Dörr
- Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin‐Schrödinger‐Str. Geb. 54, 67661 Kaiserslautern (Germany), Fax: (+49) 631‐2054676
| | - Andreas Seifert
- Institut für Chemie, Technische Universität Chemnitz, Straße der Nationen 62, 09111 Chemnitz (Germany)
| | - Zhou Zhou
- Erlangen Catalysis Resource Center (ECRC), Friedrich‐Alexander Universität Erlangen‐Nürnberg, Egerlandstraße 3, 91058 Erlangen (Germany)
| | - Martin Hartmann
- Erlangen Catalysis Resource Center (ECRC), Friedrich‐Alexander Universität Erlangen‐Nürnberg, Egerlandstraße 3, 91058 Erlangen (Germany)
| | - Robin N. Klupp Taylor
- Institute of Particle Technology, Friedrich‐Alexander Universität Erlangen‐Nürnberg, Cauerstrasse 4, 91058 Erlangen (Germany)
| | - Mingjun Jia
- Key Laboratory of Surface and Interface Chemistry of Jilin Province, College of Chemistry, Jilin University, Changchun, 130012 (China)
| | - Stefan Ernst
- Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin‐Schrödinger‐Str. Geb. 54, 67661 Kaiserslautern (Germany), Fax: (+49) 631‐2054676
| | - Werner R. Thiel
- Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin‐Schrödinger‐Str. Geb. 54, 67661 Kaiserslautern (Germany), Fax: (+49) 631‐2054676
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9
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Horikawa T, Do DD, Nicholson D. Capillary condensation of adsorbates in porous materials. Adv Colloid Interface Sci 2011; 169:40-58. [PMID: 21937014 DOI: 10.1016/j.cis.2011.08.003] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 08/26/2011] [Accepted: 08/27/2011] [Indexed: 11/30/2022]
Abstract
Hysteresis in capillary condensation is important for the fundamental study and application of porous materials, and yet experiments on porous materials are sometimes difficult to interpret because of the many interactions and complex solid structures involved in the condensation and evaporation processes. Here we make an overview of the significant progress in understanding capillary condensation and hysteresis phenomena in mesopores that have followed from experiment and simulation applied to highly ordered mesoporous materials such as MCM-41 and SBA-15 over the last few decades.
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Affiliation(s)
- Toshihide Horikawa
- School of Chemical Engineering, University of Queensland, St. Lucia, Qld 4072, Australia
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Bonnaud PA, Coasne B, Pellenq RJM. Molecular simulation of water confined in nanoporous silica. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:284110. [PMID: 21399282 DOI: 10.1088/0953-8984/22/28/284110] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper reports on a molecular simulation study of the thermodynamics, structure and dynamics of water confined at ambient temperature in hydroxylated silica nanopores of a width H = 10 and 20 Å. The adsorption isotherms for water in these nanopores resemble those observed for experimental samples; the adsorbed amount increases continuously in the multilayer adsorption regime until a jump occurs due to capillary condensation of the fluid within the pore. Strong layering of water in the vicinity of the silica surfaces is observed as marked density oscillations are observed up to 8 Å from the surface in the density profiles for confined water. Our results indicate that water molecules within the first adsorbed layer tend to adopt a H-down orientation with respect to the silica substrate. For all pore sizes and adsorbed amounts, the self-diffusivity of confined water is lower than the bulk, due to the hydrophilic interaction between the water molecules and the hydroxylated silica surface. Our results also suggest that the self-diffusivity of confined water is sensitive to the adsorbed amount.
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Affiliation(s)
- P A Bonnaud
- Centre Interdisciplinaire des Nanosciences de Marseille, CNRS and Aix-Marseille Université, Campus de Luminy, F-13288 Marseille Cedex 9, France
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Coasne B, Galarneau A, Di Renzo F, Pellenq RJM. Molecular simulation of nitrogen adsorption in nanoporous silica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:10872-10881. [PMID: 20459091 DOI: 10.1021/la100757b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This article reports on a molecular simulation study of nitrogen adsorption and condensation at 77 K in atomistic silica cylindrical nanopores (MCM-41). Two models are considered for the nitrogen molecule and its interaction with the silica substrate. In the "pea" model, the nitrogen molecule is described as a single Lennard-Jones sphere and only Lennard-Jones interactions between the nitrogen molecule and the oxygens atoms of the silica substrate are taken into account. In the "bean" model (TraPPE force field), the nitrogen molecule is composed of two Lennard-Jones sites and a linear array of three charges on the atomic positions and at the center of the nitrogen-nitrogen bond. In the bean model, the interactions between the sites on the nitrogen molecule and the Si, O, and H atoms of the substrate are the sum of the Coulombic and dispersion interactions with a repulsive short-range contribution. The data obtained with the pea and bean models in silica nanopores conform to the typical behavior observed in the experiments for adsorption/condensation in cylindrical MCM-41 nanopores; the adsorbed amount increases continuously in the multilayer adsorption regime until an irreversible jump occurs because of capillary condensation and evaporation of the fluid within the pore. Our results suggest that the pea model can be used for characterization purposes where one is interested in capturing the global experimental behavior upon adsorption and desorption in silica nanopores. However, the bean model is more suitable to investigating the details of the interaction with the surface because this model, which accounts for the partial charges located on the nitrogen atoms of the molecule (quadrupole), allows a description of the specific interactions between this adsorbate and silica surfaces (silanol groups and siloxane bridges) or grafted silica surfaces. In particular, the bean model provides a more realistic picture of nitrogen adsorption in the vicinity of silica surfaces or confined in silica nanopores, where the isosteric heat of adsorption curves show that the nitrogen molecule in this model is sensitive to the surface heterogeneity.
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Affiliation(s)
- B Coasne
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS/UM2/ENSCM/UM1, ENSCM, 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 05, France.
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12
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Lassiaz S, Galarneau A, Trens P, Labarre D, Mutin H, Brunel D. Organo-lined alumina surface from covalent attachment of alkylphosphonate chains in aqueous solution. NEW J CHEM 2010. [DOI: 10.1039/b9nj00762h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Tanchoux N, Pariente S, Trens P, Fajula F. Confinement and curvature effects as a tool for selectivity orientation in heterogeneous catalysis: Isomerisation of n-hexene over MCM-41-type catalysts. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.molcata.2008.11.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Chang SS, Clair B, Ruelle J, Beauchêne J, Di Renzo F, Quignard F, Zhao GJ, Yamamoto H, Gril J. Mesoporosity as a new parameter for understanding tension stress generation in trees. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:3023-30. [PMID: 19436045 DOI: 10.1093/jxb/erp133] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The mechanism for tree orientation in angiosperms is based on the production of high tensile stress on the upper side of the inclined axis. In many species, the stress level is strongly related to the presence of a peculiar layer, called the G-layer, in the fibre cell wall. The structure of the G-layer has recently been described as a hydrogel thanks to N(2) adsorption-desorption isotherms of supercritically dried samples showing a high mesoporosity (pores size from 2-50 nm). This led us to revisit the concept of the G-layer that had been, until now, only described from anatomical observation. Adsorption isotherms of both normal wood and tension wood have been measured on six tropical species. Measurements show that mesoporosity is high in tension wood with a typical thick G-layer while it is much less with a thinner G-layer, sometimes no more than normal wood. The mesoporosity of tension wood species without a G-layer is as low as in normal wood. Not depending on the amount of pores, the pore size distribution is always centred around 6-12 nm. These results suggest that, among species producing fibres with a G-layer, large structural differences of the G-layer exist between species.
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Affiliation(s)
- Shan-Shan Chang
- Laboratoire de Mécanique et Génie Civil, Université Montpellier 2, CNRS, Pl. E. Bataillon, cc 048, 34095 Montpellier Cedex 5, France
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Coasne B, Di Renzo F, Galarneau A, Pellenq RJM. Adsorption of simple fluid on silica surface and nanopore: effect of surface chemistry and pore shape. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7285-7293. [PMID: 18522440 DOI: 10.1021/la800567g] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This paper reports a molecular simulation study on the adsorption of simple fluids (argon at 77 K) on hydroxylated silica surfaces and nanopores. The effect of surface chemistry is addressed by considering substrates with either partially or fully hydroxylated surfaces. We also investigate the effect of pore shape on adsorption and capillary condensation by comparing the results for cylindrical and hexagonal nanopores having equivalent sections (i.e., equal section areas). Due to the increase in the polarity of the surface with the density of OH groups, the adsorbed amounts for fully hydroxylated surfaces are found to be larger than those for partially hydroxylated surfaces. Both the adsorption isotherms for the cylindrical and hexagonal pores conform to the typical behavior observed in the experiments for adsorption/condensation in cylindrical nanopores MCM-41. Capillary condensation occurs through an irreversible discontinuous transition between the partially filled and the completely filled configurations, while evaporation occurs through the displacement at equilibrium of a hemispherical meniscus along the pore axis. Our data are also used to discuss the effect of surface chemistry and pore shape on the BET method. The BET surface for fully hydroxylated surfaces is much larger (by 10-20%) than the true geometrical surface. In contrast, the BET surface significantly underestimates the true surface when partially hydroxylated surfaces are considered. These results suggest that the surface chemistry and the choice of the system adsorbate/adsorbent is crucial in determining the surface area of solids using the BET method.
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Affiliation(s)
- Benoit Coasne
- Institut Charles Gerhardt Montpellier, CNRS (UMR 5253) and Université Montpellier 2, Montpellier, France.
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Coasne B, Galarneau A, Di Renzo F, Pellenq RJM. Molecular simulation of adsorption and intrusion in nanopores. ADSORPTION 2008. [DOI: 10.1007/s10450-008-9104-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Morishige K, Ishino M. Lower closure point of adsorption hysteresis in ordered mesoporous silicas. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:11021-6. [PMID: 17894507 DOI: 10.1021/la700904d] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
To examine the nature of the lower closure point of adsorption hysteresis in ordered mesoporous silicas, we measured the temperature dependence of the adsorption-desorption isotherm of nitrogen for three kinds of ordered silicas with cagelike pores and three kinds of ordered silicas with cylindrical pores. The lower closure point pressure of nitrogen in the cagelike pores with sufficiently small necks, that is, the cavitation pressure of a confined liquid, did not depend appreciably on the cage size in the temperature region far away from a hysteresis critical temperature (Tch) but its cage-size dependence was noticeable in the vicinity of Tch. The lower closure point in the cylindrical pores depended on the pore size, and its thermal behavior was totally different from that in the cagelike pores. Nevertheless, the hysteresis critical points of nitrogen in the ordered mesoporous silicas, which are defined as a threshold of temperatures (Tch) and pressure above which reversible capillary condensation takes place in a given size and shape of pores, fell on a common line in a temperature-pressure diagram regardless of the pore geometries. We consider this finding as evidence that capillary evaporation in the cylindrical pores follows a cavitation process in the vicinity of Tch in the same way as that in the cagelike pores and also that the low limit of the hysteresis loop that has been long recognized since 1965 is due to the occurrence of a vapor bubble in a stretched metastable liquid confined to the pores with decreasing pressure (cavitation).
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Affiliation(s)
- Kunimitsu Morishige
- Department of Chemistry, Okayama University of Science, 1-1 Ridai-cho, Okayama 700-0005, Japan
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Pariente S, Papineschi PM, Trens P. Confinement effects and deviations from ideality of vapours at the adsorbed phase/gas interface. Colloids Surf A Physicochem Eng Asp 2007. [DOI: 10.1016/j.colsurfa.2006.10.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Coasne B, Galarneau A, Di Renzo F, Pellenq RJM. Gas adsorption in mesoporous micelle-templated silicas: MCM-41, MCM-48, and SBA-15. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:11097-105. [PMID: 17154590 DOI: 10.1021/la061728h] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This paper reports a molecular simulation and experimental study on the adsorption and condensation of simple fluids in mesoporous micelle-templated silicas MCM-41, MCM-48, and SBA-15. MCM-41 is described as a regular cylindrical silica nanopore, while SBA-15 is assumed to be made up of cylindrical nanopores that are connected through lateral channels. The 3D-connected topology of MCM-48 is described using a gyroid periodic minimal surface. Argon adsorption at 77 K is calculated for the three materials using Grand Canonical Monte Carlo simulations. Qualitative comparison with experiments for nitrogen adsorption in mesoporous micelle-templated silicas is made. The adsorption isotherm for SBA-15 resembles that for MCM-41. In particular, capillary condensation and evaporation are not affected by the presence of the connecting lateral channels. In contrast, the argon adsorption isotherm for MCM-48 departs from that for MCM-41 having the same pore size. While condensation in MCM-41 is a one-step process, filling of MCM-48 involves two successive jumps in the adsorbed amounts which correspond to condensation in different domains of the porosity. The condensation pressure for MCM-48 is larger than that for MCM-41. We attribute this result to the morphology of the MCM-48 surface (made up of both concave and convex regions) that differs from that for MCM-41 (concave only). Our results suggest that the pore connectivity affects pore filling when the size of the connections is comparable to that of the nanopores.
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Affiliation(s)
- Benoit Coasne
- Laboratoire de Physicochimie de la Matière Condensée, Institut Charles Gerhardt, UMR 5617 CNRS and Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
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