(278b) Exploiting a Temperature-Triggered Gating Effect in Cu(II) Based Zeolitic Imidazolate Framework for Efficient High-Temperature Hydrogen Isotope Separation

As the demand for deuterium increases in the semiconductor industry, hydrogen isotope separation technology has drawn attention exponentially. However, its natural abundance is low (0.015%) and its separation from hydrogen isotope mixture is also challenging due to its identical physicochemical properties such as size, shape, and dynamics. Currently, D₂ is separated using the Girdler sulfide process (GS) and Cryogenic distillation, but these two methods entail low separation efficiencies and high energy consumption. In order to supplement this inefficient separation method, isotope separation studies using porous materials via the kinetic quantum sieving (KQS) effect are recently attracting attention. However, the operating temperature of KQS effect is below 77 K. The Cu-based zeolitic imidazolate framework (ZIF) with 2.4 Å narrow cylindrical pores can be increased working temperature via temperature-triggered gating effect.

Herein, we report the investigation of hydrogen isotope separation using Cu-ZIF through home-built advanced-cryogenic thermal desorption spectroscopy (AC-TDS). In order to explore the separation performance according to the temperature-triggered gating effect, TDS measurement was performed at various temperatures and pressures. The D₂ uptake was obtained up to 1 mmol/g even at 100 K, and D₂/H₂ selectivity was obtained until 120 K. Cu-ZIF can be used as a promising adsorbent for increasing the KQS operating temperature.