Preparation and characterization of graphite nanosheets decorated with Fe3O4 nanoparticles used in the immobilization of glucoamylase

Graphite nanosheets (GNSs) decorated with Fe3O4 nanoparticles were synthesized by an inverse coprecipitation method. The Fe3O4–GNS hybrid material was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption isotherms, thermogravimetry and magnetic hysteresis studies. We demonstrated that the Fe3O4–GNS hybrid material had a flexible interleaved structure, a large specific surface area, high magnetic sensitivity, and good thermal stability. The amino functionalization of the material with 3-aminopropyltriethoxysilane produced a magnetic material that was used in the immobilization of glucoamylase by using glutaraldehyde as a coupling reagent. The results showed that the immobilized glucoamylase exhibited excellent activity and reusability.