A phase conversion method to anchor ZIF-8 onto a PAN nanofiber surface for CO₂ capture

Polyacrylonitrile (PAN) nanofibers were prepared by electrospinning and coated with zeolitic imidazolate
framework-8 (ZIF-8) by a phase conversion growth method and investigated for CO₂ capture. The PAN
nanofibers were pre-treated with NaOH, and further coated with zinc hydroxide, which was
subsequently converted into ZIF-8 by the addition of 2-methyl imidazolate. In the resulting flexible ZIF8/PAN composite nanofibers, ZIF-8 loadings of up to 57 wt% were achieved. Scanning electron
microscopy and energy-dispersive X-ray spectroscopy (EDS) showed the formation of evenly distributed
submicron-sized ZIF-8 crystals on the surface of the PAN nanofibers with sizes between 20 and 75 nm.
X-ray photoelectron spectroscopy (XPS) and carbon-13 nuclear magnetic resonance (13C NMR)
investigations indicated electrostatic interactions and hydrogen bonds between the ZIF-8 structure and
the PAN nanofiber. The ZIF-8/composite nanofibers showed a high BET surface area of 887 m2 g-1
. CO₂ adsorption isotherms of the ZIF-8/PAN composites revealed gravimetric CO₂ uptake capacities of
130 mg g -1 (at 298 K and 40 bar) of the ZIF-8/PAN nanofiber and stable cyclic adsorption performance.