Synthesis and Characterization of ZIF-8; Effect of Temperature and Synthesis Media (Water or Methanol)

In this work, ZIF-8 (Zeolitic Imidazole Framework with Zn nodes) as the most popular member of ZIF family was synthesized employing water or methanol as the solvent at various ligand/ metal salt ratios under different temperatures. These synthesis parameters were studied to investigate the phase purity and structural properties of the resulted products. The crystalline phase of the samples were confirmed by XRD analysis and they were characterized by FESEM and BET analysis. The results revealed that all parameters e.g. type of solvent, crystallization temperature, and ligand content have great impact on the phase purity of the synthesized ZIFs. It was revealed that the textural properties and the morphology of final products depend mostly on the type of the solvent. Using water as the synthesis media required double content of ligand respect to the media of methanol and room temperature to achieve to the pure phase of ZIF-8. In the methanol media , pure ZIF-8 was synthesized with stoichiometric ligand/metal molar ratio at both high (130°C) and low temperatures(25°C). The highest yield of ZIF-8 was 97% which was prepared from water solution at room temperature.The specific surface area was obtained 1600 and 1300, respectively, for methanol base respect to water base synthesis.

Keywords:

Metal organic framework , Zeolitic imidazole framework , ZIF-8 , synthesis