Compaction of a zirconium metal–organic framework (UiO-66) for high density hydrogen storage applications
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Royal Society of Chemistry
Abstract
We report a rare case whereby a metal–organic framework (MOF), namely UiO-66, is compacted at high
pressure ( 700 MPa or 100 000 psi) resulting in densification and improved total volumetric hydrogen
storage capacity, but crucially, without compromising the total gravimetric uptake attained in the
powdered form of the MOF. The applied compaction pressure is also unprecedented for MOFs as most
studies have shown the MOF structure to collapse when compacted at very high pressure. The UiO-66
prepared in this study retained 98% of the original surface area and microporosity after compaction at
700 MPa, and the densified pellets achieved a total H2 uptake of 5.1 wt% at 100 bar and 77 K compared
to 5.0 wt% for the UiO-66 powder. Depending on the method used to compute the volumetric uptake,
the densified UiO-66 attained unprecedented volumetric capacity at 77 K and 100 bar of up to 74 g L 1
(13 g L 1 at 298 K) compared to 29 g L 1 for the powder (6 g L 1 at 298 K) using a conventional method
that takes into account the packing density of the adsorbents, or 43 g L 1 (compared to 35 g L 1 for the
powder at 77 K and 100 bar) based on a method that uses both the single crystal and skeletal densities
of MOFs. However, regardless of the difference in the calculated values according to the two methods,
the concept of UiO-66 compaction for improving volumetric capacity without compromising
gravimetric uptake is clearly proven in this study and shows promise for the achievement of hydrogen
storage targets for a single material as set by the United States Department of Energy (DOE).
Description
Keywords
Metal–organic framework (MOF), UiO-66, High density hydrogen
Citation
Bambalaza, S.E. et al. (2018). Compaction of a zirconium metal–organic framework (UiO-66) for high density hydrogen storage applications. Journal of Materials Chemistry A, 2018.