Preparation of Magnetic CuFe 2 O 4 @Ag@ZIF-8 Nanocomposites with Highly Catalytic Activity Based on Cellulose Nanocrystals.

A facile approach was successfully developed for synthesis of cellulose nanocrystals (CNC)-supported magnetic CuFe ₂ O ₄ @Ag@ZIF-8 nanospheres which consist of a paramagnetic CuFe ₂ O ₄ @Ag core and porous ZIF-8 shell. The CuFe ₂ O ₄ nanoparticles (NPs) were first prepared in the presence of CNC and dispersant. Ag NPs were then deposited on the CuFe ₂ O ₄ /CNC composites via an in situ reduction directed by dopamine polymerization (PDA). The CuFe ₂ O ₄ /CNC@Ag@ZIF-8 nanocomposite was characterized by TEM, FTIR, XRD, N ₂ adsorption-desorption isotherms, VSM, and XPS. Catalytic studies showed that the CuFe ₂ O ₄ /CNC@Ag@ZIF-8 catalyst had much higher catalytic activity than CuFe ₂ O ₄ @Ag catalyst with the rate constant of 0.64 min ^-1 . Because of the integration of ZIF-8 with CuFe ₂ O ₄ /CNC@Ag that combines the advantaged of each component, the nanocomposites were demonstrated to have an enhanced catalytic activity in heterogeneous catalysis. Therefore, these results demonstrate a new method for the fabrication of CNC-supported magnetic core-shell catalysts, which display great potential for application in biocatalysis and environmental chemistry.