Hydrogen adsorption in a metal organic framework and a clathrate

Metal organic frameworks (MOF’s) are highly porous crystalline materials built from metal ions complexed by organic molecular spacers in a three dimensional periodic lattice (for references see e.g. Rowsell and Yaghi, Angew. Chem. Int. Ed. 2005, 44, 4670). Our hydrogen storage research in this field focussed recently on the adsorption interaction strength, since this is the parameter that determines the operation temperatures and pressures. Inelastic neutron scattering combined with first principles calculations gives remarkably good agreement and detailed information on the adsorption potential and its geometry .

Clathrate hydrates attract interest for hydrogen storage. We investigated the sII type THF stabilised clathrate hydrate using in situ neutron diffraction during loading and unloading at pressures up to 100Bar. The material appears to behave as another porous solid at temperatures above ~220K, but due to the moderately low adsorption interaction the applied pressures up to 100Bar result in a cage occupation of less than 45% only (ChemPhysChem 2008).

Left: the structure of MOF5 (2*2*2 unit cells). Right: Molecular dynamics simulation of hydrogen molecules in the MOF5 (primitive cell). The simulation temperature is 150K and the total time is 7 ps. At this temperature hydrogen spends most time in the gas phase.

Published work

  • F.M. Mulder, T.J. Dingemans, M. Wagemaker and G.J. Kearley, Modelling of hydrogen adsorption in the metal organic framework MOF5, Chemical Physics 317 (2005) 113-118. [PDF]
  • F.M. Mulder, T.J. Dingemans, H.G. Schimmel, A.J. Ramirez-Cuesta, G.J. Kearley; Hydrogen adsorption strength and sites in the metal organic framework MOF5; comparing experiment and model calculations, Chemical Physics 351 (2008) 72-76. doi:10.1016/j.chemphys.2008.03.034
  • F.M. Mulder, M. Wagemaker, L. van Eijck, G.J. Kearley; Hydrogen in porous tetrahydrofuran clathrate hydrate, ChemPhysChem 9 (2008) 1331-1337, DOI: 10.1002/cphc.200700833. 
  • Simulation of hydrogen in THF clathrate; see the H2 and THF tumble during 17ps at 270K. [WMV]
  • Experimental report on in situ D2 loading during neutron diffraction (GEM, ISIS) on THF clathrate including colour graphics. [PDF]

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