Effect of the cobalt and zinc ratio on the preparation of zeolitic imidazole frameworks (ZIFs): synthesis, characterization and supercapacitor applications

Abstract

The effect of the cobalt nitrate hexahydrate/zinc nitrate hexahydrate molar ratio on the physicochemical features of the zeolitic imidazole framework (ZIF) was studied. ZIFs were prepared by using 2-methyl imidazole as the cross-linker at room temperature without any additives in methanol solution. From the obtained results, it was found that the Co/Zn ratio has a tremendous impact on the surface area, crystallinity, pore diameter and electrochemical performance of ZIFs. Upon increasing the Co/Zn content the surface area, pore volume, pore diameter and specific capacitance decreased. The maximum BET surface area was found to be 1043.65 m² g⁻¹ for ZIF Co/Zn = 0.5. The present work offers a new intuition in relation to the role of the Co/Zn ratio in the synthesis method of ZIFs.