Isotopologue-induced structural dynamics of a triazolate metal-organic framework for efficient hydrogen isotope separation
- Linda Zhang
- Richard Röß-Ohlenroth
- Vanessa K. Peterson
- Samuel G. Duyker
- Cheng Li
- Jhonatan Luiz Fiorio
- Jan-Ole Joswig
- Robert Dinnebier
- Dirk Volkmer
- Michael Hirscher
2025-07-01
Efficient hydrogen isotope separation remains the biggest challenge due to the nearly identical physicochemical properties of H 2 and D 2 . Through in situ neutron powder diffraction and gas adsorption experiments, we investigate the hydrogen isotopologue-induced structural dynamics of the triazole-based metal-organic framework [Mn(ta) 2 ]. Gas loading induces a measurable lattice expansion, more pronounced for H 2 than D 2 , and two distinct adsorption sites are identified with a subtle but significant difference in the occupancy of H 2 and D 2 at 60 K. Cryogenic thermal desorption spectroscopy after exposure to a 1:1 isotope mixture reveals an exceptionally high D 2 /H 2 selectivity of 32.5 at 60 K. When exposed to a D 2 /H 2 mixture of 5:95, D 2 enriches to 75% in a single cycle. Given the commercial availability of the ligand and the scalability of the dia-framework topology across divalent transition metals, upscaling for industrial-scale deuterium separation is a realistic prospect. Our results give crucial molecular-level insights into isotopologue-induced structural dynamics in triazolate-based MOFs and provide guidance for improvement of isotope separation materials.