Preparation, Surface Modification, and Characteristic of α-Fe₂O₃ Nanoparticles

The α-Fe₂O₃ nanoparticles were prepared via the co-precipitation process, and they were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The effect of the water bath temperature on the average grain size of the α-Fe₂O₃ nanoparticles was investigated. The minimum grain size of the α-Fe₂O₃ nanoparticles was 19.6 nm when the water bath temperature was 40 °C. Furthermore, the α-Fe₂O₃ nanoparticles were successfully modified with silica (SiO₂) and chitosan (CTS) using the idea of nanoarchitectonics. the experimental results showed that, the average diameter of the as-prepared α-Fe₂O₃/SiO₂ nanocomposites was around 65 nm; while, the average hydrodynamic diameter of the α-Fe₂O₃/CTS nanocomposites increased gradually with the increase of chitosan in solution. When the mass ratio of chitosan and the α-Fe₂O₃ nanoparticles reached 40:1, the diameter distribution range of the α-Fe₂O₃/CTS nanocomposites was very wide of 100- 900 nm, so the mass ratio of chitosan and the α-Fe₂O₃ nanoparticles was selected from 10:1 to 20:1 to be applied.