Adsorption of CO2 by hierarchical structures of f-MWCNTs@Zn/Co-ZIF and N-MWCNTs@Zn/Co-ZIF prepared through in situ growth of ZIFs in CNTs

Zeolitic Imidazolate Frameworks (ZIFs) are one of the best porous materials for the selective adsorption of CO2. Hierarchical porous hybrid materials of Zn/Co-ZIFs (ZIF-8/ZIF-67) with carboxylate functionalized MWCNTs (fMWCNTs) or nitrogen doped MWCNTs (N-MWCNTs) have been synthesized through in-situ insertion of MWCNTs in ZIFs. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravemetric analysis (TGA), Powder X-Ray diffraction and Brunauer-Emmett-Teller (BET) techniques have been used to examine the morphology, texture, phase and surface area of as prepared hybrids. These hybrids adsorb 2.07-2.48 wt% of CO2 at 298 K and 1.0 bar pressure. f-MWCNTs@Zn/Co-ZIF adsorbed more CO2 compared to f-MWCNTs@ZIF-8 or f-MWCNTs@ZIF-67. A marginal increase in CO2 uptake was observed by hybrids composed with N-MWCNTs.