Facile synthesis behavior and CO2 adsorption capacities of Zn-based metal organic framework prepared via a microchannel reactor

• Various Zn-based metal organic frameworks (MOFs) successfully prepared via a microchannel reactor using mixed solvent of MeOH and H 2 O. • The as-obtained Zn-MOFs exhibited different morphologies and were confirmed by density functional theory (DFT) calculations. • Zn-MOF prepared by using MeOH and H 2 O performed the maximum CO 2 adsorption capacity of 3.53 mmol·g −1 and 4.36 mmol·g −1 , respectively. MOFs are traditionally synthesized via intermittent synthesis, but its synthesis process is time consuming. Furthermore, many organic solvents used in the synthesis of MOF materials severely pollute the environment. Therefore, in this work, different types of Zn-MOFs were synthesized using a microchannel reactor with various proportions of MeOH and H 2 O as solvents. Unlike the direct mixing method, the microchannel reactor could synthesize Zn-MOF structures under any solvent proportion, and different solvents had a great influence on Zn-MOF morphology. Density functional theory (DFT) calculations were conducted to explain why Zn-MOFs with varied morphologies could be synthesized in different solvents. The calculation results showed that 2-methylimidazole was easier to coordinate with the zinc ions in the MeOH solvent due to its low free energy; thus, it was easier to form three-dimensional structures. However, in the H 2 O solvent, growth stopped due to a sudden increase in free energy in the coordination process, so a two-dimensional structure appeared in the aqueous solution. Finally, Zn-MOFs with more mesoporous structures had better adsorption performance. At 1 atm and 298 K, MOF-FNP-MeOH and MOF-FNP-H 2 O performed the maximum CO 2 adsorption capacity of 3.28 mmol·g −1 and 4.09 mmol·g −1 , respectively.