Size and morphology control over MOF-74 crystals

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.