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Accurate structural characterization of mesoporous solids is of importance for potential applications and for better understanding of properties of natural porous materials. Among different characterization techniques, thermoporometry has several beneficial features, such as applicability to wetted and soft materials. In this review, we discuss recent advancements concerning nuclear magnetic resonance cryoporometry allowing for a notable improvement of the accuracy of this method. [ABSTRACT FROM AUTHOR]

Through IR microimaging the spatially and temporally resolved development of the CO2 concentration in a ZIF‐8@6FDA‐DAM mixed matrix membrane (MMM) was visualized during transient adsorption. By recording the evolution of the CO2 concentration, it is observed that the CO2 molecules propagate from the ZIF‐8 filler, which acts as a transport “highway”, towards the surrounding polymer. A high‐CO2‐concentration layer is formed at the MOF/polymer interface, which becomes more pronounced at higher CO2 gas pressures. A microscopic explanation of the origins of this phenomenon is suggested by means of molecular modeling. By applying a computational methodology combining quantum and force‐field based calculations, the formation of microvoids at the MOF/polymer interface is predicted. Grand canonical Monte Carlo simulations further demonstrate that CO2 tends to preferentially reside in these microvoids, which is expected to facilitate CO2 accumulation at the interface. [ABSTRACT FROM AUTHOR]

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In addition to the respective pore space geometries, transport enhancement in hierarchical nanoporous materials may most decisively depend on the nature of the probe molecule under consideration. As a function of these two influences, mass transfer in hierarchical materials may follow quite different scenarios. Considering mass transfer enhancement by a network of mesopores within a microporous continuum, this work presents an approach to assess these influences quantitatively. The validity of this approach is tested by dynamic Monte Carlo simulations and by comparison with the results of diffusion measurements. [ABSTRACT FROM AUTHOR]

The development of water-mediated proton-conducting materials operating above 100 °C remains challenging because the extended structures of existing materials usually deteriorate at high temperatures. A new triazolyl phosphonate metal-organic framework (MOF) [La3 L4(H2O)6]Cl ⋅ x H2O ( 1, L2−=4-(4 H-1,2,4-triazol-4-yl)phenyl phosphonate) with highly hydrophilic 1D channels was synthesized hydrothermally. Compound 1 is an example of a phosphonate MOF with large regular pores with 1.9 nm in diameter. It forms a water-stable, porous structure that can be reversibly hydrated and dehydrated. The proton-conducting properties of 1 were investigated by impedance spectroscopy. Magic-angle spinning (MAS) and pulse field gradient (PFG) NMR spectroscopies confirm the dynamic nature of the incorporated water molecules. The diffusivities, determined by PFG NMR and IR microscopy, were found to be close to that of liquid water. This porous framework accomplishes the challenges of water stability and proton conduction even at 110 °C. The conductivity in 1 is proposed to occur by the vehicle mechanism. [ABSTRACT FROM AUTHOR]

Mesoporous glasses - the leaching products of phase-separated alkali borosilicate glasses - are widely used in fundamental research and practical applications. In this work, the option to control their internal mesopore structure by varying the conditions of microphase separation has been studied. Structure and transport characterization of a family of nanoporous glasses obtained under different conditions has been performed using a combination of several experimental techniques, including gas adsorption, nuclear magnetic resonance cryoporometry and diffusometry. [ABSTRACT FROM AUTHOR]