Polymer–metal–organic framework core–shell framework nanofibers via electrospinning and their gas adsorption activities

In this study, we have fabricated of Polyacrylonitrile/Zeoliticimidazolate frameworks (PAN@ZIF-8) core–shell nanofibers by combining electrospinning techniques and the MOF synthesis method. In the first step, 2MI ligand was dispersed on PAN by using electrospinning, and then 2MI was made to coordinate Zn2+ ions derived from a zinc acetate solution. In the second step, the nanofiber mats were immersed in a ZIF-8 seed solution, and continuous and compact ZIF-8 was formed on the PAN surface by a second round of crystal growth. Analyses of XPS results and of SEM and TEM images revealed the core–shell structure of PAN@ZIF-8 nanofibers, and showed them to have a uniform nanoshell but a variety of crystal diameters. In addition, the core–shell PAN@ZIF-8 nanofibers were found to display unique properties such as a stable and flexible structure and an excellent gas adsorption capability. Our findings suggest that the core–shell PAN@ZIF-8 nanofiber mats may form a good filter material because of their gas absorption properties and because of the structural flexibility and stability of ZIF-8.