Comparing the influence of framework type on H2 absorption in hypothetical and existing clathrasils: A grand canonical Monte Carlo study

Annemieke W.C. Van Den Berg, Martijn A. Zwijnenburg, Stefan T. Bromley*, Edwin Flikkema, Robert G. Bell, Jacobus C. Jansen, Joop Schoonman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (SciVal)

Abstract

The influence of the framework type, in particular the influence of the type of cage, on the hydrogen absorption capacity in a range of clathrasil structures (frameworks having Si6O6 as their largest ring aperture) is investigated by means of grand canonical Monte Carlo simulations. Our systematic analysis includes twelve existing clathrasils and for the first time we also calculate practical properties for seven energetically viable hypothetical clathrasil frameworks. Hydrogen absorption isotherms are calculated for every material at 78, 85, and 90 K for 0-12 bar, and at 273 and 573 K for 0-3000 bar. At all investigated conditions, cages with a small volume (<400 Å3) give rise to high absorption energies due to the larger attractive contact area between the cage wall and hydrogen. Despite this higher absorption energy, the H2 loading on a weight basis is relatively low in these small cages, because of the high internal surface-to-volume ratio, leaving little void space for the H2 molecule. As a result, the existing and hypothetical structures with the largest cages, LTN and Dt3_819, exhibit the highest absorption capacities. All investigated hypothetical clathrasils show similar absorption behavior to the existing clathrasils, supporting other evidence that these currently hypothetical materials are likely to be synthesized.

Original languageEnglish
Pages (from-to)3285-3290
Number of pages6
JournalJournal of Materials Chemistry
Volume16
Issue number32
DOIs
Publication statusPublished - 2006

Fingerprint

Dive into the research topics of 'Comparing the influence of framework type on H2 absorption in hypothetical and existing clathrasils: A grand canonical Monte Carlo study'. Together they form a unique fingerprint.

Cite this