The effects of various activation methods on UiO-66 Metal−Organic Framework.

UiO-66 is a high important prototypical zirconium-based metal−organic framework (MOF) compound because of its excellent stabilities not typically found in common porous MOFs. In the crystal structure, each Zr metal center is fully coordinated by 12 organic linkers to form a highly connected framework [1]. In this work showed that by changing the Synthesis methods and the synthesis time, the linker vacancies can be modified systematically, leading to dramatically enhanced porosity. The results showed a porous metal−organic framework based on benzene 1,4-dicarboxylic acid ligand that its specifications are dependent on different activation methods [2]. A key aspect to the realization of high porosity is the removal of guest molecules from the framework while still maintaining its structural integrity ( activation ). The highlights utilized strategies for activating MOFs are: (i) conventional heating and vacuum; (ii) solvent-exchange; (iii) supercritical CO2 (scCO2) exchange; (iv) freeze-drying; and (v) chemical treatment [3]. The surface area of prepared sample via conventional heating and vacuum method increased from 50 m2/g to 570 m2/g, via the solvent-exchange method increased from 570 m2/g to 870 m2/g and via the freeze-drying method increased from 870 m2/g to 1200 m2/g.