NMR diffusometry with guest molecules in nanoporous materials.

Application of pulsed field gradient (PFG) NMR to studying molecular diffusion in beds of nanoporous materials has given rise to novel insights and paradigm shifts in our understanding, which are reviewed in the present contribution. This gain in information is, in particular, related to the ability of PFG NMR to discriminate between various mechanisms affecting mass transfer in such systems. Examples include, inter alia, the sensitivity of PFG NMR toward transport enhancement in pore hierarchies as well as toward transport resistances acting, in addition to the diffusional resistance of the genuine pore space, either on the crystal surfaces or in their interior.