Preparation of ZIF-67@PAN Nanofibers for CO2 Capture: Effects of Solvent and Time on Particle Morphology

Advanced materials including metal–organic frameworks (MOFs) are a critical piece of the puzzle in the search for solutions to various scientific and technological challenges, such as climate change due to the ever-increasing emissions of greenhouse gas. There is intense interest in MOFs due to their potential use for a variety of environmental applications, including catalysis and gas storage. In this work, we specifically focus on the in situ growth of zeolitic imidazolate framework-67 (ZIF-67) on poly(acrylonitrile) (PAN) fibers and its potential application in CO2 adsorption. Nanofibers were spun from a solution containing PAN and cobalt (II) nitrate hexahydrate using electrospinning. Then, the fibers were immersed in solution with 2-methylimidazole for different time durations. Via the diffusion of the cobalt ions through the fibers and interaction with the ligands in the solution, ZIF-67 was formed. From analysis via SEM, FTIR, PXRD, and CO2 adsorption, it is evident that varying different parameters—the type of solvent, immersion time, and ligand concentration—affected the morphology of the formed ZIF-67. It was found that immersion for 4 h in 6.0 mg/mL of ligands in methanol created the ZIF-67@PAN best suited for CO2 adsorption, showing a CO2 uptake of 0.4 mmol/g at 1.2 bar and 273 K.