Comparative Gas Sorption and Cryoporometry Study of Mesoporous Glass Structure: Application of the Serially Connected Pore Model

Enninful, Henry R. N. B.; Schneider, Denis; Hoppe, Antonia; König, Sandra; Fröba, Michael; Enke, Dirk; Valiullin, Rustem

doi:10.3389/fchem.2019.00230

Cited by 15 publications

(21 citation statements)

References 64 publications

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“…Nitrogen sorption at 77 K and NMR cryoporometry of water on heating and cooling cycles over several temperatures were employed for this study. Detailed experimental protocols on the methods used have been described elsewhere [ 25 ]. The raw data from the measurements without corrections for the adsorbed film thickness and NFLs have been used.…”

Section: Methodsmentioning

confidence: 99%

On the Comparative Analysis of Different Phase Coexistences in Mesoporous Materials

2022

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Alterations of fluid phase transitions in porous materials are conventionally employed for the characterization of mesoporous solids. In the first approximation, this may be based on the application of the Kelvin equation for gas–liquid and the Gibbs–Thomson equation for solid–liquid phase equilibria for obtaining pore size distributions. Herein, we provide a comparative analysis of different phase coexistences measured in mesoporous silica solids with different pore sizes and morphology. Instead of comparing the resulting pore size distributions, we rather compare the transitions directly by using a common coordinate for varying the experiment’s thermodynamic parameters based on the two equations mentioned. Both phase transitions in these coordinates produce comparable results for mesoporous solids of relatively large pore sizes. In contrast, marked differences are found for materials with smaller pore sizes. This illuminates the fact that, with reducing confinement sizes, thermodynamic fluctuations become increasingly important and different for different equilibria considered. In addition, we show that in the coordinate used for analysis, mercury intrusion matches perfectly with desorption and freezing transitions.

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Section: Methodsmentioning

confidence: 99%

On the Comparative Analysis of Different Phase Coexistences in Mesoporous Materials

2022

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“…It is worth noting that, irrespective of the apparent symmetry of the hysteresis loop for SBA-15-O, IPM cannot simultaneously capture the freezing and melting behaviors. 100 As demonstrated in Figure 12a, with one and the same PSD the melting and freezing branches cannot be matched simultaneously. In contrast, the SKV theory is able to reproduce not only both boundary transitions but also the freezing scans (Figure 12b).…”

Section: ■ Correlation With Experimentsmentioning

confidence: 99%

Impact of Geometrical Disorder on Phase Equilibria of Fluids and Solids Confined in Mesoporous Materials

et al. 2021

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Porous solids used in practical applications often possess structural disorder over broad length scales. This disorder strongly affects different properties of the substances confined in their pore spaces. Quantifying structural disorder and correlating it with the physical properties of confined matter is thus a necessary step toward the rational use of porous solids in practical applications and process optimization. The present work focuses on recent advances made in the understanding of correlations between the phase state and geometric disorder in nanoporous solids. We overview the recently developed statistical theory for phase transitions in a minimalistic model of disordered pore networks: linear chains of pores with statistical disorder. By correlating its predictions with various experimental observations, we show that this model gives notable insight into collective phenomena in phase-transition processes in disordered materials and is capable of explaining self-consistently the majority of the experimental results obtained for gas−liquid and solid−liquid equilibria in mesoporous solids. The potentials of the theory for improving the gas sorption and thermoporometry characterization of porous materials are discussed.

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“…Despite some advantages, NMR cryoporometry suffers from a poor description of the solid–liquid equilibria in confined spaces with complex geometries. Over the years, we have extended the frontiers of the understanding of solid–liquid equilibria in materials with long cylindrical pores and random porous materials. , As a step forward, we have described in this work a detailed analysis of a complex model pore network which employs transition kernels for the structural elucidation of mesoporous solids with spherical nanocages.…”

Section: Discussionmentioning

confidence: 99%

“…To obtain the PSD, an inverse solution has also been developed . As a general approach for describing phase equilibria, the SCPM has enabled a deeper understanding of the freezing–melting of water in tubular pores with pore wall corrugations. , Coupled with the kernel-based approach, it has been able to unlock the disorder effects in complex pore networks . Regardless of the pore morphology, incorporating all representative physical phenomena in kernels may present a more accurate structural analysis of mesoporous materials.…”

Section: Introductionmentioning

confidence: 99%

Nuclear Magnetic Resonance Cryoporometry Study of Solid–Liquid Equilibria in Interconnected Spherical Nanocages

Enninful

Schneider

Rudolph³

et al. 2021

J. Phys. Chem. C

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In this work, a combined experimental and theoretical study of solid−liquid phase equilibria confined in mesoporous solids composed of spherical cages connected via smaller-sized cylindrical irregular channels is presented. The experimental data on phase equilibria obtained using nuclear magnetic resonance (NMR) cryoporometry with water as a probe liquid are analyzed using transition kernels developed for the spherical pores. They accurately predict the variation of the nonfrozen water layer thickness with temperature as well as the positions of the solid−liquid and liquid−solid transition temperatures. By analyzing the melting and freezing transitions as well as scanning freezing transitions in materials with different properties of the interconnecting pore network achieved by different synthesis conditions, an accurate information on the textural properties and phase transition processes is obtained. The results obtained are compared to the structural information obtained using other experimental techniques such as small-angle X-ray scattering and gas sorption.

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Comparative Gas Sorption and Cryoporometry Study of Mesoporous Glass Structure: Application of the Serially Connected Pore Model

Cited by 15 publications

References 64 publications

On the Comparative Analysis of Different Phase Coexistences in Mesoporous Materials

On the Comparative Analysis of Different Phase Coexistences in Mesoporous Materials

Impact of Geometrical Disorder on Phase Equilibria of Fluids and Solids Confined in Mesoporous Materials

Nuclear Magnetic Resonance Cryoporometry Study of Solid–Liquid Equilibria in Interconnected Spherical Nanocages

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