(128f) Advanced Characterization of Nanoporous Materials: Effect of Pore Size and Temperature on the Adsorption and Phase Behavior of Wetting and Nonwetting Fluids

During the last decades major advances in understanding the adsorption and phase behavior of fluids confined in ordered nanoporous materials have been made, which led to significant progress in the physisorption characterization methodology (summarized in the 2015 IUPAC report on physisorption characterization [1]). Here we discuss progress and challenges for the physisorption characterization of nanoporous solids exhibiting various levels of porosity from micro- to macropores [2]. While physisorption allows one to assess micro- and mesopores, a widely employed method for textural analysis of macroporous materials is based on the intrusions/extrusion of mercury, which does not wet the majority of surfaces at room temperature. Furthermore, in order to assess aspects of surface chemistry, adsorption methods have been applied which combine wetting fluids (e.g. argon and nitrogen at their boiling temperature) with adsorbates where the wetting behavior is appreciable controlled by surface chemistry (e.g. water adsorption at room temperature. see ref [2). We demonstrate that an improved understanding of confined geometry effects on the adsorption and phase behavior of wetting and non-wetting fluids allows one to arrive at a more reliable structural characterization of complex, nanoporous pore networks.

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References

[1] M. Thommes, K. Kaneko, A.V. Neimark, J.P. Olivier, F. Rodriguez Reinoso, J. Rouquerol and K.S.W Sing, “Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution “ (IUPAC Technical Report), Pure Appl. Chem. 87, 1051 (2015)

[2] K. A. Cychosz, R. Guillet-Nicolas, J. Garcia-Martinez, J., M. Thommes, “Recent Advances in the textural characterization of hierarchically structured nanoporous materials” Chem. Soc. Rev. 46, 389, (2017)