Multivariate Flexible Framework with High Usable Hydrogen Capacity in a Reduced Pressure Swing Process

Arijit Halder, Ryan Klein, Sarah Shulda, Gavin McCarver, Philip Parilla, Hiroyasu Furukawa, Craig Brown, C. McGuirk

Research output: Contribution to journalArticlepeer-review

8 Scopus Citations

Abstract

Step-shaped adsorption-desorption of gaseous payloads by flexible metal-organic frameworks can facilitate the delivery of large usable capacities with significantly reduced energetic penalties. This is desirable for the storage, transport, and delivery of H2, as prototypical adsorbents require large swings in pressure and temperature to achieve usable capacities approaching their total capacities. However, the weak physisorption of H2 typically necessitates undesirably high pressures to induce the framework phase change. As de novo design of flexible frameworks is exceedingly challenging, the ability to intuitively adapt known frameworks is required. We demonstrate that the multivariate linker approach is a powerful tool for tuning the phase change behavior of flexible frameworks. In this work, 2-methyl-5,6-difluorobenzimidazolate was solvothermally incorporated into the known framework CdIF-13 (sod-Cd(benzimidazolate)2), resulting in the multivariate framework sod-Cd(benzimidazolate)1.87(2-methyl-5,6-difluorobenzimidazolate)0.13 (ratio = 14:1), which exhibited a considerably reduced stepped adsorption threshold pressure while maintaining the desirable adsorption-desorption profile and capacity of CdIF-13. At 77 K, the multivariate framework exhibits stepped H2 adsorption with saturation below 50 bar and minimal desorption hysteresis at 5 bar. At 87 K, saturation of step-shaped adsorption occurs by 90 bar, with hysteresis closing at 30 bar. These adsorption-desorption profiles enable usable capacities in a mild pressure swing process above 1 mass %, representing 85-92% of the total capacities. This work demonstrates that the desirable performance of flexible frameworks can be readily adapted through the multivariate approach to enable efficient storage and delivery of weakly physisorbing species.

Original languageAmerican English
Pages (from-to)8033-8042
Number of pages10
JournalJournal of the American Chemical Society
Volume145
Issue number14
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-85074

Keywords

  • DFT
  • flexible metal-organic framework
  • hydrogen storage
  • isotherm
  • MOF
  • multivariate
  • powder X-ray diffraction

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