Simulating Enhanced Methane Deliverable Capacity in Intrinsically Flexible MOFs

M. Witman, B. Wright, and B. Smit, Simulating Enhanced Methane Deliverable Capacity of Guest Responsive Pores in Intrinsically Flexible MOFs J Phys Chem Lett, 5929 (2019) doi: 10.1021/acs.jpclett.9b02449


A novel computational procedure, based on the principles of flat-histogram Monte Carlo, is developed for the facile prediction of the adsorption thermodynamics of intrinsically flexible adsorbents. We then demonstrate how an accurate prediction of methane deliverable capacity in a metal-organic framework (MOF) with significant intrinsic flexibility requires use of such a method. Dynamic side chains in the framework respond to methane adsorbates and reorganize to exhibit a more conducive pore space at high adsorbate densities, while simultaneously providing a less conducive pore space at low adsorbate densities. This “responsive pore” MOF achieves ~20 % higher deliverable capacity than if the framework were rigid and elucidates a strategy for designing high deliverable capacity MOFs in the future.