An Ultramicroporous Ni‐Based MOF for Xe‐selective Capture and Ar/Kr/Xe Gas‐Phase Preparative Chromatography Separation in Liquid Fluoride Thorium Reactor Off‐Gases

ABSTRACT

Efficient xenon separation is important for noble‐gas management in liquid fluoride thorium reactor (LFTR) off‐gas systems. Here, JUC‐86, an ultramicroporous Ni‐based metal‐organic framework, is investigated for Xe‐selective capture and Ar/Kr/Xe separation. JUC‐86 features a crystallographic aperture of approximately 5.2 Å and model‐derived pore widths of 4.1‐5.2 Å. At 298 K and 1 bar, the adsorption capacities of Xe, Kr, and Ar reach 75.6, 57.2, and 17.3 cm ³ g ⁻¹ , respectively. IAST calculations, isosteric heats of adsorption, and host–guest calculations consistently indicate a stronger affinity toward Xe. Under continuous‐flow conditions, JUC‐86 exhibits reproducible Xe/Kr breakthrough separation, with an average Xe capture capacity of 1.41 mmol g ⁻¹ and Kr productivity above 99.9% purity. The material also captures trace Xe from dilute Xe/Kr/Ar streams and enables effective preparative chromatographic separation of Ar, Kr, and Xe over varied operating conditions. Bonding‐based analysis further suggests a meaningful degree of intrinsic γ‐radiation tolerance. These results demonstrate the potential of JUC‐86 for Xe‐selective capture and chromatographic noble‐gas separation in advanced nuclear off‐gas management.