Principles of Chemisorption

Freund, Hans‐Joachim

doi:10.1002/9783527610044.hetcat0075

Cited by 9 publications

(1 citation statement)

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“…As a key quantity of heterogeneous catalysis with (metal) surfaces, the sticking coefficient (Freund 2008) is defined as the fraction of molecules which, upon colliding with the surface of the catalyst, is not reflected into the gas phase. With the advent of microimaging it has now become possible to also determine experimentally the related information about a nanoporous solid, namely the probability S np that, upon encountering a nanoporous particle, a molecule shall be able to get through its external surface into its genuine pore space.…”

Section: Sticking Probabilitiesmentioning

confidence: 99%

Application of microimaging to diffusion studies in nanoporous materials

et al. 2020

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Microimaging on the basis of, respectively, interference microscopy and IR microscopy permit the observation of the distribution of guest molecules in nanoporous solids and their variation with time. Thus attainable knowledge of both concentration gradients and diffusion fluxes provides direct access to the underlying diffusion phenomena. This includes, in particular, the measurement of transport diffusion under transient, i. e. under non-equilibrium conditions, and of self- or tracer diffusion on considering the rate of tracer exchange. Correlating the difference in guest concentration close to the external surface to its equilibrium value with the influx into the nanoporous solid, microimaging does as well allow the direct determination of surface resistances. Examples illustrating the variety of information thus attainable include the comparison of mass transfer under equilibrium and non-equilibrium conditions, single- and multicomponent diffusion and chemical reactions. They, finally, introduce into the potentials of microimaging for an in-depth study of mass transfer in mixed-matrix membranes. This tutorial review may serve as first introduction into the topic. Further references are linked for the interested reader.

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Section: Sticking Probabilitiesmentioning

confidence: 99%