(520c) The Effect of Intrinsic Framework Flexibility on Adsorption Properties in Metal-Organic Frameworks: A Computational Exploration

Metal-organic frameworks (MOFs) have shown great potential for applications such as gas storage and adsorptive separation. In these applications, flexibility in these nanoporous materials plays a critical role to tune material performance. In this work, we use computational methods to explore the effect of adsorption induced framework flexibility on its adsorption properties. For the study, we selected ~300 MOFs from CoreMOFs database covering a wide range of pore diameters, surface areas and type of linkers. To obtain systematic insights into the adsorption induced flexibility on framework’s properties, we develop a methodology combining ab-initio and molecular simulations that captures the framework dynamics at high loadings of adsorbates to predict selectivity. We have applied these methods to a range of adsorbates of industrially relevant mixtures for separations, which includes CH₄, CO_2, ethane, ethene, propane, propene, butane, ethylbenzene and xylene isomers, in selected MOFs. A detailed comparison study of adsorption properties was done with and without accounting the flexibility in ~300 MOFs for 13 adsorbates divided into 5 mixtures. We conclude that flexible simulations can be critical to correctly model adsorption in MOFs.