A review on zeolite imidazole frameworks: synthesis, properties, and applications

Zeolitic imidazolate frameworks (ZIFs) consist of transition metal ions (Zinc or Cobalt) and imidazolate (Im) linkers in tetrahedral coordination surrounded by nitrogen atoms from the five-membered imidazole ring serving as a bridging linker, i.e. a link connecting the metal centres in the three-dimensional framework. The crystal structures of ZIFs share the same topologies as those that can be found in aluminosilicate zeolites. ZIFs have advantages over zeolites such that the hybrid framework structures are expected to have more flexibility in surface modification. Due to their interesting properties such as high porosity, high surface area, exceptional thermal and chemical stability, ZIFs are very attractive materials with potential applications including gas sorption, gas separation, and catalysis. Over a decade tremendous work has been carried out to develop ZIFs in synthesis and its various applications. In this review, we have briefly composed the different methods for the synthesis of ZIFs such as solvent-based and solvent-free methods. In addition, its thermal and chemical properties and potential applications in the field of adsorption, separation, catalysis, sensing, and drug delivery have been summarized.