Preparation and characterization of magnetic Fe3O4/CRGO nanocomposites for enzyme immobilization

A one-step hydrothermal procedure to form Fe3O4 nanospheres on chemically reduced graphene oxide (CRGO) surfaces was proposed, and these nanocomposites were used as substrates for enzyme immobilization. The as-prepared Fe3O4/CRGO nanocomposites were characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), FT-IR and vibrating sample magnetometer. Fe3O4 microspheres are randomly distributed on graphene sheets, and the average diameter of Fe3O4 microspheres is about 260 nm. Horseradish peroxidase (HRP) was used as a model enzyme to investigate the immobilization activity. The HRP loading was 23.3 mg/g supports and retained 70% of the first use after ten cycles. The catalyzed capability of immobilized HRP was investigated and the immobilized HRP exhibited broader pH stability and excellent reusability. The results show that the Fe3O4/CRGO nanocomposites are appropriate for the immobilization of enzyme, and could have potential use in practical.