Toward separation of hydrogen isotopologues by exploiting zero-point energy difference at strongly attractive adsorption site models

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Toshiki Wulf - , Leipzig University (Author)
  • Thomas Heine - , Leipzig University (Author)

Abstract

Recent reports on hydrogen isotope separation in metal-organic frameworks are rationalized by the presence of undercoordinated metal sites. In this work, we screen undercoordinated divalent metals for their performance as hydrogen separating agents in common chemical environments (as free dications, as part of M2(HCOO)4 paddlewheels and in metal porphyrins). We calculate heat of adsorption and selectivity using the Langmuir model and the density-functional-based potential energy surface. Our calculations show a strong metal ion dependence of the adsorption energy in paddlewheels, but rather small impact of metal choice in stable porphyrins. D2-over-H2 selectivities reach top values of 12 for CO2+ paddlewheels, while only oxidatively unstable porphyrins incorporating Cr2+, V2+, and Ti2+ show high selectivities.

Details

Original languageEnglish
Article numbere25545
JournalInternational Journal of Quantum Chemistry
Volume118
Issue number9
Publication statusPublished - 5 May 2018
Peer-reviewedYes
Externally publishedYes

Keywords

Keywords

  • density-functional theory, hydrogen isotopes, metal-organic frameworks, porphyrins