(129h) High Yield Stoichiometric Synthesis of ZIF-8 Nanoparticles Using Novel Reactor

Zeolitic imidazolate Frameworks (ZIFs) are chemical and thermally stable sub-class of metal organic frameworks. The desirable molecular sieving properties of ZIFs make these materials an interesting candidate for energy-efficient separation techniques, mainly membrane and adsorption techniques. The particle size becomes an important criterion for membrane applications as bigger particles can pose diffusion limitations. The main challenge for greater utilization of ZIFs is the difficulty to synthesize material with uniform particle size and high surface areas at large scales, while achieving high yields.

In this work, a scalable, solution phase synthesis is demonstrated for ZIF-8 nanoparticles with uniform diameters in the range of 40-80 nm. ZIF-8 is synthesized with 89% yield using stoichiometric precursor concentrations using a novel reactor. Turbulence created by the reactor provides homogeneous conditions in the reaction volume resulting in improved yield. The surface area and micropore volume of the synthesized materials confirm the high quality of products. The reactor was studied to determine the effect of different synthesis parameters including ligand to metal ratio, base concentration, and mixing intensity. The base concentration has the most effect on the product size, morphology, and yield. The versatility of the reactor is shown by synthesizing ZIF-67 with 79% yield. Further, a larger reactor was constructed and tested, demonstrating that the method can be scaled to increase productivity. Overall, this work presents a versatile and scalable route for nanoparticle synthesis.