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Abstract
AbstractNanoporous solids are ubiquitous in chemical, energy, and environmental processes, where controlled transport of molecules through the pores plays a crucial role. They are used as sorbents, chromatographic or membrane materials for separations, and as catalysts and catalyst supports. Defined as materials where confinement effects lead to substantial deviations from bulk diffusion, nanoporous materials include crystalline microporous zeotypes and metal–organic frameworks (MOFs), and a number of semi-crystalline and amorphous mesoporous solids, as well as hierarchically structured materials, containing both nanopores and wider meso- or macropores to facilitate transport over macroscopic distances. The ranges of pore sizes, shapes, and topologies spanned by these materials represent a considerable challenge for predicting molecular diffusivities, but fundamental understanding also provides an opportunity to guide the design of new nanoporous materials to increase the performance of transport limited processes. Remarkable progress in synthesis increasingly allows these designs to be put into practice. Molecular simulation techniques have been used in conjunction with experimental measurements to examine in detail the fundamental diffusion processes within nanoporous solids, to provide insight into the free energy landscape navigated by adsorbates, and to better understand nano-confinement effects. Pore network models, discrete particle models and synthesis-mimicking atomistic models allow to tackle diffusion in mesoporous and hierarchically structured porous materials, where multiscale approaches benefit from ever cheaper parallel computing and higher resolution imaging. Here, we discuss synergistic combinations of simulation and experiment to showcase theoretical progress and computational techniques that have been successful in predicting guest diffusion and providing insights. We also outline where new fundamental developments and experimental techniques are needed to enable more accurate predictions for complex systems.
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2
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Abstract
AbstractLabeling in diffusion measurements by pulsed field gradient (PFG) NMR is based on the observation of the phase of nuclear spins acquired in a constant magnetic field with purposefully superimposed field gradients. This labeling does in no way affect microdynamics and provides information about the probability distribution of molecular displacements as a function of time. An introduction of the measuring principle is followed by a detailed description of the ranges of measurements and their limitation. Particular emphasis is given to an explanation of possible pitfalls in the measurements and the ways to circumvent them. Showcases presented for illustrating the wealth of information provided by PFG NMR include a survey on the various patterns of concentration dependence of intra-particle diffusion and examples of transport inhibition by additional transport resistances within the nanoporous particles and on their external surface. The latter information is attained by combination with the outcome of tracer exchange experiments, which are shown to become possible via a special formalism of PFG NMR data analysis. Further evidence provided by PFG NMR concerns diffusion enhancement in pore hierarchies, diffusion anisotropy and the impact of diffusion on chemical conversion in porous catalysts. A compilation of the specifics of PFG NMR and of the parallels with other measurement techniques concludes the paper.
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3
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Hwang S, Kärger J. NMR diffusometry with guest molecules in nanoporous materials. Magn Reson Imaging 2019; 56:3-13. [DOI: 10.1016/j.mri.2018.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/20/2018] [Accepted: 08/23/2018] [Indexed: 01/22/2023]
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Jee AY, Yanai N, Granick S. Comparing Geometry and Chemistry When Confined Molecules Diffuse in Monodisperse Metal-Organic Framework Pores. J Phys Chem Lett 2018; 9:6399-6403. [PMID: 30362354 DOI: 10.1021/acs.jpclett.8b02810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The monodisperse pore structure of MOFs (metal-organic frameworks) is advantageous for investigating how porosity influences diffusion. Here we report translational and rotational diffusion using fluorescence correlation spectroscopy and time-correlated single-photon counting, using the three-dimensional pores of the zeolitic-like metal-organic framework family. We compare the influence of size and electric charge as well as dependence on pore size that we controlled through postsynthetic cation-exchange modifications. Charge-charge interactions with the MOF appeared to produce transient adsorption, manifested as a relatively fast and a slower diffusion process, but diffusants without net electric charge displayed a single diffusion process. Obtained from this family of guest molecules selected to be fluorescent, these findings suggest potentially useful general design rules to predict how pore size, guest size, and host-guest interaction control guest mobility within nanopores. With striking fidelity, diffusion coefficient scales with the ratio of cross-sectional areas of diffusant and host pores when charge is taken into account.
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Affiliation(s)
- Ah-Young Jee
- Center for Soft and Living Matter , Institute for Basic Science (IBS) , Ulsan 44919 , South Korea
| | - Nobuhiro Yanai
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS) , Kyushu University y, 744 Moto-oka , Nishi-ku, Fukuoka 819-0395 , Japan
| | - Steve Granick
- Center for Soft and Living Matter , Institute for Basic Science (IBS) , Ulsan 44919 , South Korea
- Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , South Korea
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5
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Birkmann F, Pasel C, Luckas M, Bathen D. Adsorption Thermodynamics and Kinetics of Light Hydrocarbons on Microporous Activated Carbon at Low Temperatures. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b00678] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Florian Birkmann
- University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
| | - Christoph Pasel
- University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
| | - Michael Luckas
- University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
| | - Dieter Bathen
- University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
- IUTA e.V., Bliersheimer Straße 58-60, 47229 Duisburg, Germany
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Hwang S, Parditka B, Cserháti C, Erdélyi Z, Gläser R, Haase J, Kärger J, Schmidt W, Chmelik C. IR Microimaging of Direction-Dependent Uptake in MFI-Type Crystals. CHEM-ING-TECH 2017. [DOI: 10.1002/cite.201700128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Seungtaik Hwang
- Leipzig University; Faculty of Physics and Earth Sciences; Linnéstrasse 5 04103 Leipzig Germany
| | - Bence Parditka
- University of Debrecen; Department of Solid State Physics; P.O. Box 400 4002 Debrecen Hungary
| | - Csaba Cserháti
- University of Debrecen; Department of Solid State Physics; P.O. Box 400 4002 Debrecen Hungary
| | - Zoltán Erdélyi
- University of Debrecen; Department of Solid State Physics; P.O. Box 400 4002 Debrecen Hungary
| | - Roger Gläser
- Leipzig University; Institute of Chemical Technology; Linnéstrasse 3 04103 Leipzig Germany
| | - Jürgen Haase
- Leipzig University; Faculty of Physics and Earth Sciences; Linnéstrasse 5 04103 Leipzig Germany
| | - Jörg Kärger
- Leipzig University; Faculty of Physics and Earth Sciences; Linnéstrasse 5 04103 Leipzig Germany
| | - Wolfgang Schmidt
- Max-Planck-Institut für Kohlenforschung; Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Christian Chmelik
- Leipzig University; Faculty of Physics and Earth Sciences; Linnéstrasse 5 04103 Leipzig Germany
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8
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Schneider D, Mehlhorn D, Zeigermann P, Kärger J, Valiullin R. Transport properties of hierarchical micro–mesoporous materials. Chem Soc Rev 2016; 45:3439-67. [DOI: 10.1039/c5cs00715a] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This work provides an overview of different experimental techniques of diffusion measurements in porous materials and discusses transport properties of several classes of hierarchically organized micro-mesoporous materials.
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Affiliation(s)
- Daniel Schneider
- Faculty of Physics and Earth Sciences
- University of Leipzig
- Leipzig
- Germany
| | - Dirk Mehlhorn
- Faculty of Physics and Earth Sciences
- University of Leipzig
- Leipzig
- Germany
| | - Philipp Zeigermann
- Faculty of Physics and Earth Sciences
- University of Leipzig
- Leipzig
- Germany
| | - Jörg Kärger
- Faculty of Physics and Earth Sciences
- University of Leipzig
- Leipzig
- Germany
| | - Rustem Valiullin
- Faculty of Physics and Earth Sciences
- University of Leipzig
- Leipzig
- Germany
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9
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Pochert A, Schneider D, Haase J, Linden M, Valiullin R. Diffusion and Molecular Exchange in Hollow Core-Shell Silica Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:10285-10295. [PMID: 26327167 DOI: 10.1021/acs.langmuir.5b02367] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The diffusion behavior of small molecules in hollow core-shell nanocapsules was studied using pulsed field gradient NMR. By purposefully selecting the liquid saturating the hollow core and the porous shell and the solvent between the nanocapsules, two different situations corresponding to the excluded and admitted molecular exchange between the intra- and intercapsule liquids at the external boundary of the nanoparticles were covered. In the former case, corresponding to the reflective boundary condition for the molecules approaching the nanocapsule boundary, restricted diffusion in the complex pore space formed by the hollow core and the mesoporous shell was observed. The time-dependent diffusivities measured in the experiment were inter-related with the geometry of the intraparticle pore space. The thus assessed structural information was found to be in a good agreement with that provided by electron microscopy. In the case of the molecular exchange occurring between the two pools of molecules in the nanocapsules and between them, the diffusive dynamics of only the molecules remaining in the nanocapsules during the entire observation times was studied.
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Affiliation(s)
- A Pochert
- Institute of Inorganic Chemistry 2, University of Ulm , Ulm, 89081, Germany
| | | | | | - M Linden
- Institute of Inorganic Chemistry 2, University of Ulm , Ulm, 89081, Germany
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Huber P. Soft matter in hard confinement: phase transition thermodynamics, structure, texture, diffusion and flow in nanoporous media. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:103102. [PMID: 25679044 DOI: 10.1088/0953-8984/27/10/103102] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Spatial confinement in nanoporous media affects the structure, thermodynamics and mobility of molecular soft matter often markedly. This article reviews thermodynamic equilibrium phenomena, such as physisorption, capillary condensation, crystallisation, self-diffusion, and structural phase transitions as well as selected aspects of the emerging field of spatially confined, non-equilibrium physics, i.e. the rheology of liquids, capillarity-driven flow phenomena, and imbibition front broadening in nanoporous materials. The observations in the nanoscale systems are related to the corresponding bulk phenomenologies. The complexity of the confined molecular species is varied from simple building blocks, like noble gas atoms, normal alkanes and alcohols to liquid crystals, polymers, ionic liquids, proteins and water. Mostly, experiments with mesoporous solids of alumina, gold, carbon, silica, and silicon with pore diameters ranging from a few up to 50 nm are presented. The observed peculiarities of nanopore-confined condensed matter are also discussed with regard to applications. A particular emphasis is put on texture formation upon crystallisation in nanoporous media, a topic both of high fundamental interest and of increasing nanotechnological importance, e.g. for the synthesis of organic/inorganic hybrid materials by melt infiltration, the usage of nanoporous solids in crystal nucleation or in template-assisted electrochemical deposition of nano structures.
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Affiliation(s)
- Patrick Huber
- Hamburg University of Technology (TUHH), Institute of Materials Physics and Technology, Eißendorfer Str. 42, D-21073 Hamburg-Harburg (Germany
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11
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Farmahini AH, Bhatia SK. Differences in the adsorption and diffusion behaviour of water and non-polar gases in nanoporous carbon: role of cooperative effects of pore confinement and hydrogen bonding. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2014.976640] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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13
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Diffusion properties of liquid crystal-based microemulsions. Colloid Polym Sci 2014. [DOI: 10.1007/s00396-014-3288-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Farmahini AH, Shahtalebi A, Jobic H, Bhatia SK. Influence of Structural Heterogeneity on Diffusion of CH 4 and CO 2 in Silicon Carbide-Derived Nanoporous Carbon. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2014; 118:11784-11798. [PMID: 24932319 PMCID: PMC4051255 DOI: 10.1021/jp502929k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/07/2014] [Indexed: 06/03/2023]
Abstract
We investigate the influence of structural heterogeneity on the transport properties of simple gases in a Hybrid Reverse Monte Carlo (HRMC) constructed model of silicon carbide-derived carbon (SiC-DC). The energy landscape of the system is determined based on free energy analysis of the atomistic model. The overall energy barriers of the system for different gases are computed along with important properties, such as Henry constant and differential enthalpy of adsorption at infinite dilution, and indicate hydrophobicity of the SiC-DC structure and its affinity for CO2 and CH4 adsorption. We also study the effect of molecular geometry, pore structure and energy heterogeneity considering different hopping scenarios for diffusion of CO2 and CH4 through ultramicropores using the Nudged Elastic Band (NEB) method. It is shown that the energy barrier of a hopping molecule is very sensitive to the shape of the pore entry. We provide evidence for the influence of structural heterogeneity on self-diffusivity of methane and carbon dioxide using molecular dynamics simulation, based on a maximum in the variation of self-diffusivity with loading. A comparison of the MD simulation results with self-diffusivities from quasi-elastic neutron scattering (QENS) measurements and, with macroscopic uptake-based low-density transport coefficients, reveals the existence of internal barriers not captured in MD simulation and QENS experiments. Nevertheless, the simulation and macroscopic uptake-based diffusion coefficients agree within a factor of 2-3, indicating that our HRMC model structure captures most of the important energy barriers affecting the transport of CH4 in the nanostructure of SiC-DC.
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Affiliation(s)
- Amir H. Farmahini
- School
of Chemical Engineering, The University
of Queensland, QLD 4072, Australia
| | - Ali Shahtalebi
- School
of Chemical Engineering, The University
of Queensland, QLD 4072, Australia
| | - Hervé Jobic
- Institut
de Recherches sur la Catalyse et l’Environnement de Lyon, CNRS, Université Lyon 1, 2 Ave. Albert Einstein, 69626 Villeurbanne, France
| | - Suresh K. Bhatia
- School
of Chemical Engineering, The University
of Queensland, QLD 4072, Australia
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15
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Zalesskiy SS, Danieli E, Blümich B, Ananikov VP. Miniaturization of NMR systems: desktop spectrometers, microcoil spectroscopy, and "NMR on a chip" for chemistry, biochemistry, and industry. Chem Rev 2014; 114:5641-94. [PMID: 24779750 DOI: 10.1021/cr400063g] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Sergey S Zalesskiy
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , Moscow, 119991, Russia
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16
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Shakhov A, Reichenbach C, Kondrashova D, Zeigermann P, Mehlhorn D, Enke D, Valiullin R. Exploring Internal Structure of Nanoporous Glasses Obtained by Leaching of Phase-Separated Alkali Borosilicate Glasses. CHEM-ING-TECH 2013. [DOI: 10.1002/cite.201300088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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Arnold L, Averlant G, Marx S, Weickert M, Müller U, Mertel J, Horch C, Peksa M, Stallmach F. Metal Organic Frameworks for Natural Gas Storage in Vehicles. CHEM-ING-TECH 2013. [DOI: 10.1002/cite.201300093] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Gounaris CE, First EL, Floudas CA. Estimation of diffusion anisotropy in microporous crystalline materials and optimization of crystal orientation in membranes. J Chem Phys 2013; 139:124703. [DOI: 10.1063/1.4821583] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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19
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Einicke WD, Enke D, Dvoyashkin M, Valiullin R, Gläser R. The Mechanism of Pseudomorphic Transformation of Spherical Silica Gel into MCM-41 Studied by PFG NMR Diffusometry. MATERIALS 2013; 6:3688-3709. [PMID: 28788300 PMCID: PMC5452651 DOI: 10.3390/ma6093688] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 11/20/2022]
Abstract
The pseudomorphic transformation of spherical silica gel (LiChrospher® Si 60) into MCM-41 was achieved by treatment at 383 K for 24 h with an aqueous solution of cetyltrimethylammonium hydroxide (CTAOH) instead of hexadecyltrimethylammonium bromide (CTABr) and NaOH. The degree of transformation was varied via the ratio of CTAOH solution to initial silica gel rather than synthesis duration. The transformed samples were characterized by N2 sorption at 77 K, mercury intrusion porosimetry, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thus, MCM-41 spheres with diameters of ca. 12 μm, surface areas >1000 m2 g−1, pore volumes >1 cm3 g−1 and a sharp pore width distribution, adjustable between 3.2 and 4.5 nm, were obtained. A thorough pulsed field gradient nuclear magnetic resonance (PFG NMR) study shows that the diffusivity of n-heptane confined in the pores of the solids passes through a minimum with progressing transformation. The final product of pseudomorphic transformation to MCM-41 does not exhibit improved transport properties compared to the initial silica gel. Moreover, the PFG NMR results support that the transformation occurs via formation and subsequent growth of domains of <1 μm containing MCM-41 homogeneously distributed over the volume of the silica spheres.
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Affiliation(s)
- Wolf-Dietrich Einicke
- Institute of Chemical Technology, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany.
| | - Dirk Enke
- Institute of Chemical Technology, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany.
| | - Muslim Dvoyashkin
- Institute of Experimental Physics I, Universität Leipzig, Linnéstr. 5, 04103 Leipzig, Germany.
| | - Rustem Valiullin
- Institute of Experimental Physics I, Universität Leipzig, Linnéstr. 5, 04103 Leipzig, Germany.
| | - Roger Gläser
- Institute of Chemical Technology, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany.
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20
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Bonilla MR, Titze T, Schmidt F, Mehlhorn D, Chmelik C, Valiullin R, Bhatia SK, Kaskel S, Ryoo R, Kärger J. Diffusion Study by IR Micro-Imaging of Molecular Uptake and Release on Mesoporous Zeolites of Structure Type CHA and LTA. MATERIALS 2013; 6:2662-2688. [PMID: 28811401 PMCID: PMC5521224 DOI: 10.3390/ma6072662] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/12/2013] [Accepted: 06/17/2013] [Indexed: 01/12/2023]
Abstract
The presence of mesopores in the interior of microporous particles may significantly improve their transport properties. Complementing previous macroscopic transient sorption experiments and pulsed field gradient NMR self-diffusion studies with such materials, the present study is dedicated to an in-depth study of molecular uptake and release on the individual particles of mesoporous zeolitic specimens, notably with samples of the narrow-pore structure types, CHA and LTA. The investigations are focused on determining the time constants and functional dependences of uptake and release. They include a systematic variation of the architecture of the mesopores and of the guest molecules under study as well as a comparison of transient uptake with blocked and un-blocked mesopores. In addition to accelerating intracrystalline mass transfer, transport enhancement by mesopores is found to be, possibly, also caused by a reduction of transport resistances on the particle surfaces.
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Affiliation(s)
- Mauricio Rincon Bonilla
- Faculty of Physics and Earth Science, University of Leipzig, Linnéstr. 5, D-04103 Leipzig, Germany.
- School of Chemical Engineering, University of Queensland, Brisbane QLD 4072, Australia.
| | - Tobias Titze
- Faculty of Physics and Earth Science, University of Leipzig, Linnéstr. 5, D-04103 Leipzig, Germany.
| | - Franz Schmidt
- Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden, Germany.
| | - Dirk Mehlhorn
- Faculty of Physics and Earth Science, University of Leipzig, Linnéstr. 5, D-04103 Leipzig, Germany.
| | - Christian Chmelik
- Faculty of Physics and Earth Science, University of Leipzig, Linnéstr. 5, D-04103 Leipzig, Germany.
| | - Rustem Valiullin
- Faculty of Physics and Earth Science, University of Leipzig, Linnéstr. 5, D-04103 Leipzig, Germany.
| | - Suresh K Bhatia
- School of Chemical Engineering, University of Queensland, Brisbane QLD 4072, Australia.
| | - Stefan Kaskel
- Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden, Germany.
| | - Ryong Ryoo
- Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Korea.
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
| | - Jörg Kärger
- Faculty of Physics and Earth Science, University of Leipzig, Linnéstr. 5, D-04103 Leipzig, Germany.
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Handford TP, Pérez-Reche FJ, Taraskin SN. Capillary condensation in one-dimensional irregular confinement. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:012139. [PMID: 23944446 DOI: 10.1103/physreve.88.012139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 05/30/2013] [Indexed: 06/02/2023]
Abstract
A lattice-gas model with heterogeneity is developed for the description of fluid condensation in finite sized one-dimensional pores of arbitrary shape. Mapping to the random-field Ising model allows an exact solution of the model to be obtained at zero-temperature, reproducing the experimentally observed dependence of the amount of fluid adsorbed in the pore on external pressure. It is demonstrated that the disorder controls the sorption for long pores and can result in H2-type hysteresis. Finite-temperature Metropolis dynamics simulations support analytical findings in the limit of low temperatures. The proposed framework is viewed as a fundamental building block of the theory of capillary condensation necessary for reliable structural analysis of complex porous media from adsorption-desorption data.
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Affiliation(s)
- Thomas P Handford
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom.
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Probing hysteresis during sorption of cyclohexane within mesoporous silica using NMR cryoporometry and relaxometry. J Colloid Interface Sci 2013; 398:168-75. [DOI: 10.1016/j.jcis.2013.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 01/29/2013] [Accepted: 02/01/2013] [Indexed: 11/21/2022]
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23
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Wu SC, Cheng ZM, Liu P, Yu YM, Jin J, Zhou ZM. Pore network effects under the reduction of catalyst size at elevated temperatures. Chem Eng Sci 2013. [DOI: 10.1016/j.ces.2013.01.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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24
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Zeigermann P, Valiullin R. Transport properties of gas-expanded liquids in bulk and under confinement. J Supercrit Fluids 2013. [DOI: 10.1016/j.supflu.2012.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Alonso B, Marichal C. Solid-state NMR studies of micelle-templated mesoporous solids. Chem Soc Rev 2013; 42:3808-20. [DOI: 10.1039/c2cs35368g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kärger J, Valiullin R. Mass transfer in mesoporous materials: the benefit of microscopic diffusion measurement. Chem Soc Rev 2013; 42:4172-97. [DOI: 10.1039/c3cs35326e] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Koptyug IV. MRI of mass transport in porous media: drying and sorption processes. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2012; 65:1-65. [PMID: 22781314 DOI: 10.1016/j.pnmrs.2011.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 12/05/2011] [Indexed: 06/01/2023]
Affiliation(s)
- Igor V Koptyug
- International Tomography Center, SB RAS, 3A Institutskaya Str., Novosibirsk 630090, Russian Federation.
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Zeigermann P, Naumov S, Mascotto S, Kärger J, Smarsly BM, Valiullin R. Diffusion in hierarchical mesoporous materials: applicability and generalization of the fast-exchange diffusion model. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:3621-3632. [PMID: 22260082 DOI: 10.1021/la2047432] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Transport properties of cyclohexane confined to a silica material with an ordered, bimodal pore structure have been studied by means of pulsed field gradient nuclear magnetic resonance. A particular organization of the well-defined pore structure, composed of a collection of spatially ordered, spherical mesopores interconnected via narrow worm-like pores, allowed for a quantitative analysis of the diffusion process in a medium with spatially ordered distribution of the fluid density for a broad range of the gas-liquid equilibria. The measured diffusion data were interpreted in terms of effective diffusivities, which were determined within a microscopic model considering long-range molecular trajectories constructed by assembling the alternating pieces of displacement in the two constituting pore spaces. It has further been found that for the system under study, in particular, and for mesoporous materials with multiple porosities, in general, this generalized model simplifies to the conventional fast-exchange model used in the literature. Thus, not only was justification of the applicability of the fast-exchange model to a diversity of mesoporous materials provided, but the diffusion parameters entering the fast-exchange model were also exactly defined. The equation resulting in this way was found to nicely reproduce the experimentally determined diffusivities, establishing a methodology for targeted fine-tuning of transport properties of fluids in hierarchical materials with multiple porosities.
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Affiliation(s)
- P Zeigermann
- Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany
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Han S, Hermans TM, Fuller PE, Wei Y, Grzybowski BA. Transport into Metal-Organic Frameworks from Solution Is Not Purely Diffusive. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201108492] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Transport into Metal-Organic Frameworks from Solution Is Not Purely Diffusive. Angew Chem Int Ed Engl 2012; 51:2662-6. [DOI: 10.1002/anie.201108492] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Indexed: 11/07/2022]
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Bhatia SK, Nicholson D. Modeling Self-Diffusion of Simple Fluids in Nanopores. J Phys Chem B 2011; 115:11700-11. [DOI: 10.1021/jp206811a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Suresh K. Bhatia
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
| | - David Nicholson
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
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Mazza MG, Greschek M, Valiullin R, Schoen M. Role of stringlike, supramolecular assemblies in reentrant supernematic liquid crystals. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:051704. [PMID: 21728553 DOI: 10.1103/physreve.83.051704] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Indexed: 05/31/2023]
Abstract
Using a combination of isothermal-isobaric Monte Carlo and microcanonical molecular dynamics we investigate the relation between structure and self-diffusion in various phases of a model liquid crystal using the Gay-Berne-Kihara potential. These molecules are confined to a mesoscopic slit pore with atomically smooth substrate surfaces. As reported recently [seeM. G. Mazza et al., Phys. Rev. Lett. 105, 227802 (2010)], a reentrant nematic (RN) phase may form at sufficiently high pressures and densities. This phase is characterized by a high degree of nematic order and a substantially enhanced self-diffusivity in the direction of the director n that exceeds that of the lower-density nematic and an intermittent smectic-A phase by about an order of magnitude. Here we demonstrate that the unique transport behavior in the RN phase may be linked to a confinement-induced packing effect that causes the formation of supramolecular, stringlike conformations. The strings consist of several molecules traveling in the direction of n as individual "trains" consisting of chains of molecular "cars."
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Affiliation(s)
- Marco G Mazza
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Berlin, Germany
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Furtado F, Galvosas P, Gonçalves M, Kopinke FD, Naumov S, Rodríguez-Reinoso F, Roland U, Valiullin R, Kärger J. Guest Diffusion in Interpenetrating Networks of Micro- and Mesopores. J Am Chem Soc 2011; 133:2437-43. [DOI: 10.1021/ja109235c] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Filipe Furtado
- Department of Environmental Engineering, UFZ−Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany
- Department of Interface Physics, University of Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany
| | - Petrik Galvosas
- Department of Interface Physics, University of Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
| | - Maraisa Gonçalves
- Departamento de Química Inorgánica, Universidad de Alicante, Apartado 99, 03080 Alicante, Spain
| | - Frank-Dieter Kopinke
- Department of Environmental Engineering, UFZ−Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Sergej Naumov
- Department of Interface Physics, University of Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany
| | | | - Ulf Roland
- Department of Environmental Engineering, UFZ−Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Rustem Valiullin
- Department of Interface Physics, University of Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany
| | - Jörg Kärger
- Department of Interface Physics, University of Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany
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Valiullin R, Kärger J. The Impact of Mesopores on Mass Transfer in Nanoporous Materials: Evidence of Diffusion Measurement by NMR. CHEM-ING-TECH 2011. [DOI: 10.1002/cite.201000208] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Koller H, Weiss M. Solid state NMR of porous materials : zeolites and related materials. Top Curr Chem (Cham) 2011; 306:189-227. [PMID: 21452082 DOI: 10.1007/128_2011_123] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Solid state NMR spectroscopy applied to the science of crystalline micro- and mesoporous silica materials over the past 10 years is reviewed. A survey is provided of framework structure and connectivity analyses from chemical shift effects of various elements in zeolites including heteroatom substitutions, framework defects and pentacoordinated silicon for zeolites containing fluoride ions. New developments in the field of NMR crystallography are included. Spatial host-guest ordering and confinement effects of zeolite-sorbate complexes are outlined, with special emphasis on NMR applications utilizing the heteronuclear dipolar interaction. The characterization of zeolite acid sites and in situ NMR on catalytic conversions is also included. Finally, the motion of extra-framework cations is investigated in two tutorial cases of sodium hopping in sodalite and cancrinite.
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Affiliation(s)
- Hubert Koller
- Institute of Physical Chemistry, University of Münster, Corrensstr. 28/30, 48149, Münster, Germany.
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Mazza MG, Greschek M, Valiullin R, Kärger J, Schoen M. Entropy-driven enhanced self-diffusion in confined reentrant supernematics. PHYSICAL REVIEW LETTERS 2010; 105:227802. [PMID: 21231424 DOI: 10.1103/physrevlett.105.227802] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Indexed: 05/30/2023]
Abstract
We present a molecular dynamics study of reentrant nematic phases using the Gay-Berne-Kihara model of a liquid crystal in nanoconfinement. At densities above those characteristic of smectic A phases, reentrant nematic phases form that are characterized by a large value of the nematic order parameter S≃1. Along the nematic director these "supernematic" phases exhibit a remarkably high self-diffusivity, which exceeds that for ordinary, lower-density nematic phases by an order of magnitude. Enhancement of self-diffusivity is attributed to a decrease of rotational configurational entropy in confinement. Recent developments in the pulsed field gradient NMR technique are shown to provide favorable conditions for an experimental confirmation of our simulations.
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Affiliation(s)
- Marco G Mazza
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
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37
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Kimmich R, Fatkullin N. Anisotropy of the Segment Mobility versus Self- and Pair-Correlation Functions in Polymer Melts under Mesoscopic Confinement. Macromolecules 2010. [DOI: 10.1021/ma102117f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Nail Fatkullin
- Department of Physics, Kazan Federal University (former Kazan State University), Kazan 420008, Tatarstan, Russia
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Chmelik C, Kärger J. In situ study on molecular diffusion phenomena in nanoporous catalytic solids. Chem Soc Rev 2010; 39:4864-84. [PMID: 20972502 DOI: 10.1039/c0cs00100g] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
As an omnipresent phenomenon in nature, diffusion is among the rate-determining processes in many technological processes. This is in particular true for catalytic conversion in nanoporous materials. We provide a critical review of the possibilities of exploring diffusion phenomena over microscopic dimensions in such media by direct experimental observation. By monitoring the probability distribution of molecular displacements as a function of time, the pulsed field gradient technique of NMR (PFG NMR) records the rate of molecular re-distribution. By varying the observation time, PFG NMR is thus able to trace even hierarchies of transport resistances as occurring, e.g., in catalyst particles in the form of binder-compacted assemblages of zeolite crystallites. Alternatively, and complementary to this information, interference microscopy (IFM) and IR microscopy (IRM) are able to follow the evolution of intracrystalline concentration profiles during uptake and release. This allows, in particular, an accurate quantification of the transport resistances on the surface of the individual crystallites and of the probability that reactant molecules from the gas phase, upon colliding with the external surface, are able to penetrate through such "surface barriers" into the crystal bulk phase. Being able to distinguish between different molecular species, IRM is able to record the evolution of intracrystalline concentration profiles even during multi-component adsorption and catalytic reactions (169 references).
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Affiliation(s)
- Christian Chmelik
- University of Leipzig, Faculty for Physics and Earth Sciences, Linnéstraße 5, D-04103 Leipzig, Germany.
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Chigada P, Wang J, Al-Duri B, Wood J, Rigby S. Modelling of pore structure evolution during catalyst deactivation and comparison with experiment. Chem Eng Sci 2010. [DOI: 10.1016/j.ces.2010.07.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kärger J, Chmelik C, Heinke L, Valiullin R. A new view of diffusion in nanoporous materials. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201000038] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Protasova LN, Rebrov EV, Glazneva TS, Berenguer-Murcia A, Ismagilov ZR, Schouten JC. Control of the thickness of mesoporous titania films for application in multiphase catalytic microreactors. J Catal 2010. [DOI: 10.1016/j.jcat.2009.07.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Weber D, Sederman AJ, Mantle MD, Mitchell J, Gladden LF. Surface diffusion in porous catalysts. Phys Chem Chem Phys 2010; 12:2619-24. [DOI: 10.1039/b921210h] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Iacob C, Sangoro JR, Papadopoulos P, Schubert T, Naumov S, Valiullin R, Kärger J, Kremer F. Charge transport and diffusion of ionic liquids in nanoporous silica membranes. Phys Chem Chem Phys 2010; 12:13798-803. [DOI: 10.1039/c004546b] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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