Size and morphology control over MOF-74 crystals

Abstract

Precise control of the size and morphology of metal–organic framework (MOF) crystals is challenging yet critical for the expansion of the application potential of MOF materials. This work presents a detailed investigation of the impact of various synthetic conditions such as reactant ratio, acidity, capping agent, reaction solution (H₂O, ethanol and DMF) etc. on the size and morphology of Mg-MOF-74, a classical MOF with record high CO₂ uptake capacity. By varying these fabrication parameters and modulators, the morphology and size of crystals can be precisely tuned in the nanometer to micrometer range. Particularly, the nanosized flaky Mg-MOF-74 crystals with an aspect ratio of ∼0.5 were synthesized for the first time by varying the amount of water. The MOF-74 crystals with different size and morphologies are good candidates for more advanced applications favored by crystal size and morphology control.