Magnetic Induction Framework Synthesis: A General Route to the Controlled Growth of Metal-Organic Frameworks

A magnetic induction process known as MIFS to rapidly synthesize magnetic Mg-MOF-74 composites driven by magnetic nanoparticles (MNP)-delivered localized magnetic induction heat was developed. The yield and size of the resulting magnetic framework composites (MFCs) can be effectively regulated by the reaction time, MNPs concentration, and the strength of the applied magnetic field. In particular, the optimum yield of MOF components in MFCs can reach up to 91.1% after 8.0 h of reaction under the investigated conditions, 12.5-fold higher than that of the reaction performed with traditional hot plate heating for 23 h. All the resulting MFCs exhibited uniform distribution in their matrices and no MNP aggregates were observed. With the localized magnetic induction heating, the growth of Mg-MOF-74 crystals on the inner walls of the reactor can be effectively avoided. The formation of free MOF crystals also can be effectively suppressed by simply controlling reaction time. In addition, MNP-delivered localized heating involved in MIFS makes MOF production more energy efficient compared with the traditional hot plate heating. The resulting magnetic Mg-MOF-74 showed up to 98.4% CO2 desorption capacity.