Exploiting the Specific Isotope-Selective Adsorption of Metal–Organic Framework for Hydrogen Isotope Separation

Adsorptive separation using narrow-micropore adsorbents has demonstrated the potential to separate hydrogen isotopes. In this work, we employed an isotope-responsive separation using cobalt formate. A D 2 -responsive third sorption step was revealed, and consequently, a noticeable difference was observed in the uptakes of D 2 and H 2 . This may have resulted from the additional space created for D 2 due to its dense packing, as DFT calculations revealed that cobalt formate possesses 2.26 kJ/mol higher binding strength for D 2 than for H 2 . The exploitation of this D 2 -responsive third sorption step renders a promising separation performance, with a D 2 /H 2 selectivity of up to 44 at 25 K/1 bar. Lastly, cobalt formate was synthesized on a gram scale here, which makes it a prospect for commercialization.