(468f) Morphology Based Adsorption Kinetics of a Selectively Modulated Metal-Organic Framework

Metal organic frameworks (MOFs) have gained interest in recent decades due to their high porosity, tunable pore aperture, and easily synthesized crystalline structures for applications such as catalysis, separations, sensing, gas storage, medicine, and energy. MOFs are composed of metal ions or oxo-metallic secondary building units (SBUs) coordinated with organic linkers to form a porous, open framework. The rational selection of these components in addition to modulating species and structure directing agents allows for the control of pore geometry and size at the surface of MOF crystals. By tuning the crystal size, morphology, and the dominant surface pore as determined by the crystal orientation, it is possible to tune the selectivity of a MOF to enhance the adsorption and separation of a given species of gas molecule. Previous results have shown that a copper based MOF with anisotropic pore distribution in the unit cell, [Cu₂(ndc)₂(dabco)]_n, can show controlled crystalline morphology through the addition of modulators during the synthesis. In this work, we leverage the modulation of crystallization growth processes to synthesize MOF surfaces with selective pore sizes and orientations. We demonstrate how changing the morphology of MOFs can affect the selectivity and adsorption kinetics of select species. The relationship between particle morphology, surface pore size and the adsorbed species is discussed. Additionally, tuning MOF morphology and orientation for higher selectivity and separations is discussed.