Hysteresis in porosimetry

Kloubek, J.

doi:10.1016/0032-5910(81)85005-x

Cited by 97 publications

(75 citation statements)

References 23 publications

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“…This suggests less fluorine in the regions occupied by platinum clusters. The intrusion and extrusion pressures have then ( Figure 5(b)) been converted to pore radius using the standard Kloubek 13 correlation, which removes the effects of contact angle hysteresis. From Figure 5 it can be shown that the modal intrusion radius is ~10-20 nm.…”

Section: Computerised X-ray Tomography (Cxt)mentioning

confidence: 99%

Pore Structural Characterization of Fuel Cell Layers Using Integrated Mercury Porosimetry and Computerized X-ray Tomography

Malik

Smith

Sharman

et al. 2016

Ind. Eng. Chem. Res.

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The pore structure of the cathode catalyst layer of proton-exchange membrane (PEM) fuel cells is a major factor influencing cell performance. The nanostructure of the catalyst layer has been probed, using a novel combination of mercury porosimetry with computerised X-ray tomography (CXT), even though the nanopores were below the nominal CXT resolution. The method allows probing of the macroscopic spatial variability in the accessibility of the nanostructure. In particular, mercury entrapment within the catalyst layer showed a pronounced regular spatial patterning corresponding to the already higher X-ray absorbing regions of the fresh catalyst layer. The initial, greater X-ray absorption was due to a higher local concentration of carbon-supported platinum catalyst. This was due to segregation of ionomer away from these areas, caused by the particular screen printing catalyst layer deposition method used, which both enhanced the accessibility of the origin regions and, concomitantly, reduced the accessibility of the destination regions.

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Section: Computerised X-ray Tomography (Cxt)mentioning

confidence: 99%

Pore Structural Characterization of Fuel Cell Layers Using Integrated Mercury Porosimetry and Computerized X-ray Tomography

Malik

Smith

Sharman

et al. 2016

Ind. Eng. Chem. Res.

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Section: Mercury Porosimetrymentioning

confidence: 99%

“…However, it has been shown (Kloubek 1981) that both the contact angle h and surface tension c vary with the radius of curvature of the meniscus, and that the contact angle depends upon whether the meniscus is advancing or receding. More recently (Kloubek 1981;Rigby 2002) expressions for the product c.cos h have been obtained that incorporate these effects. These expressions have been derived by measuring the pressure p at which mercury enters or leaves a model porous medium, with a well-defined structure, for which an independent measure of pore size r, such as via electron microscopy, is available (Liabastre and Orr 1978).…”

Section: Mercury Porosimetrymentioning

confidence: 99%

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Techniques for direct experimental evaluation of structure–transport relationships in disordered porous solids

et al. 2016

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Determining structure-transport relationships is critical to optimising the activity and selectivity performance of porous pellets acting as heterogeneous catalysts for diffusion-limited reactions. For amorphous porous systems determining the impact of particular aspects of the void space on mass transport often requires complex characterization and modelling steps to deconvolve the specific influence of the feature in question. These characterization and modelling steps often have limited accuracy and precision. It is the purpose of this work to present a case-study demonstrating the use of a more direct experimental evaluation of the impact of pore network features on mass transport. The case study evaluated the efficacy of the macropores of a bidisperse porous foam structure on improving mass transport over a purely mesoporous system. The method presented involved extending the novel integrated gas sorption and mercury porosimetry method to include uptake kinetics. Results for the new method were compared with those obtained by the alternative NMR cryodiffusometry technique, and found to lead to similar conclusions. It was found that the experimentally-determined degree of influence of the foam macropores was in line with expectations from a simple resistance model for a disconnected macropore network.

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“…More recently [12,13] correlations for the term coshave been obtained that take into account these effects. These correlations have been determined by calibrating the pressure p at which mercury invades into, or retreats from, a model porous medium with a regular structure (e,g, controlled pore glass) against an independent measure of pore size r, such as electron microscopy [14]).…”

Section: Mercury Porosimetrymentioning

confidence: 99%

Detection of the delayed condensation effect and determination of its impact on the accuracy of gas adsorption pore size distributions

Rigby

Hasan

Hitchcock

et al. 2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk 1 normally requiring assumptions about the correct model for data analysis. In this work we present a novel method to both expand the range, and obtain greater accuracy, for the information obtained from the main boundary adsorption isotherms by using a combination of data obtained for two adsorptives, namely nitrogen and argon, both before and after mercury porosimetry. The method makes use of the fact that nitrogen and argon apparently 'see' a different pore geometry following mercury entrapment, with argon, relatively, 'ignoring' new metal surfaces produced by mercury porosimetry. The new method permits the study of network and pore-pore co-operative effects during adsorption that substantially affect the accuracy of the characteristic parameters, such as modal pore size, obtained for disordered materials. These effects have been explicitly quantified, for a typical sol-gel silica catalyst support material as a case study. The technique allowed the large discrepancies between modal pore sizes obtained from standard gas adsorption and mercury thermoporometry methods to be attributed to the network-based delayed condensation effect, rather than spinodal adsorption. Once the network-based delayed condensation effect had been accounted for, the simple cylindrical pore model and macroscopic thermodynamic Kelvin-Cohan equation were then found sufficient to accurately describe adsorption in the material studied, rather than needing a more complex microscopic theory. Hence, for disordered mesoporous solids, a proper account of inter-pore interactions is more important than that of intra-pore adsorbate density distribution, to obtain accurate pore size distributions. Detection of the Delayed Condensation Effect and Determination of its

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Hysteresis in porosimetry

Cited by 97 publications

References 23 publications

Pore Structural Characterization of Fuel Cell Layers Using Integrated Mercury Porosimetry and Computerized X-ray Tomography

Pore Structural Characterization of Fuel Cell Layers Using Integrated Mercury Porosimetry and Computerized X-ray Tomography

Techniques for direct experimental evaluation of structure–transport relationships in disordered porous solids

Detection of the delayed condensation effect and determination of its impact on the accuracy of gas adsorption pore size distributions

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