Assessing guest diffusivities in porous hosts from transient concentration profiles

  • chair:

    Heinke, L. / Tzoulaki, D. / Chmelik, C. / Hibbe, F. / van Baten, J. / Lim, H. / Li, J. / Krishna, R. / Kärger, J. (2009)
  • place:

    Physical Review Letters 102 (2009), 6, 065901
  • Date: 2009

  • Heinke, L. / Tzoulaki, D. / Chmelik., C. / Hibbe, F. / van Baten, J. / Lim, H. / Li, J. / Krishna, R. / Kärger, J. (2009): „Assessing guest diffusivities in porous hosts from transient concentration profiles“. In: Physical Review Letters 102 (2009), 6, 065901

Abstract

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Using the short-chain-length alkanes from ethane to n-butane as guest molecules, transient concentration profiles during uptake or release (via interference microscopy) and tracer exchange (via IR microimaging) in Zn(tbip), a particularly stable representative of a novel family of nanoporous materials (the metal organic frameworks), were recorded.

Analyzing the spatiotemporal dependence of the profiles provides immediate access to the transport diffusivities and self-diffusivities, yielding a data basis of unprecedented reliability for mass transfer in nanoporous materials. As a particular feature of the system, self- and transport diffusivities may be combined to estimate the rate of mutual passages of the guest molecules in the chains of pore segments, thus quantifying departure from a genuine single-file system.