3.4. Synthesis of ZIF-67/CNFs Composite

In this study, Co(NO₃)₂·6H₂O and mIM were used as precursors to produce ZIF-67 nanocrystals. First of all, the CNFs and Co(NO₃)₂·6H₂O (with the mass ratio of 1:1) were dispersed in 40 mL of methanol with slight stirring for 1 h at 45 ℃. After that, above solution was added into 40 mL of 2 mol L⁻¹ mIM methanol solution. The solution gradually became purple and was incubated for 24 h at room temperature. The obtained products were gathered, washed for several times with ethanol and collected by centrifugation. For comparison, pure ZIF-67 nanocrystals were prepared by similar procedure except from the addition of CNFs.