Green synthesis of zirconium-based MOF-808 by utilizing sustainable synthesis approaches

Versatile nature of zirconium (IV)based metal-organic frameworks makes them an attractivecandidate for many applications such as catalysis, energy storage, gas separation, etc., due to their high chemical, mechanical and thermal stability, and high porosity. Batch-wise synthesis incurs extra costs and time while restricting reaction control and structural tunability with precision control for customized crystal sizes. Here, we synthesize zirconium-based MOF-808 under three distinct operating conditions: continuous microfluidic synthesis, microwave-assisted, and ultrasound-assisted synthesis. Zirconium-based MOF-808 has been synthesized in green solvents - water and ethanol at a constant metal salt:ligand ratio of 3:1 (Zr:BTC). These synthesis approaches have been demonstrated,and MOF-808 samples were analyzed using sophisticatedanalytical techniques, including field emission scanning electron microscopy (FE-SEM), Powder X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) analysis and Fourier transform infrared spectroscopy (FTIR). Analysis results show that the microfluidics approach exhibits good results among all others in terms of morphology, surface area, and thermal stability from all three approaches. This paper provides new avenues of synthesis approach routes on a lab-scale environment that is a first step toward the switch to more effective MOF synthesis approaches at the industrial scale.