A joint experimental and computational study of noble gas adsorption in the metal-organic framework (MOF) material HKUST-1 has been carried out. Using a standard gas adsorption analyzer fitted with a cryostat, isotherms were measured for Xe, Kr, Ar, and Ne at optimum temperatures for the determination of loading-dependent heats of adsorption using the Clausius-Clapeyron equation. Direct calorimetric measurements for Kr and Xe adsorption provide comparable heats of adsorption. A detailed analysis of the experimental data alongside complementary grand canonical Monte Carlo (GCMC) simulations led to the conclusion that the strongest binding for noble gases occurs in and around the small tetrahedral pockets and not at the accessible Cu(II) sites in the structure. Synchrotron X-ray and neutron powder diffraction experiments with in situ gas loading confirm the assignment of preferred binding sites inferred from the adsorption measurements and simulations.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films