Preparation of water-soluble magnetite nanocrystals through hydrothermal approach

Water-soluble Fe3O4 nanocrystals have been prepared through hydrothermal approach. These nanocrystals capped with C6H6O6 (the oxidation state of ascorbic acid) could be readily dispersed in hydrated aqueous systems. The final product was characterized with X-ray powder diffraction (XRD), transmission electron microscope (TEM), Fourier Transform Infrared and X-ray photoelectron spectroscopy. From XRD patterns, we confirm the product to be Fe3O4. The nanoparticles several nanometers long were well dispersed as shown in TEM image. Magnetic hysteresis loop measurements showed that the Fe3O4 nanocrystals display superparamagnetism. A possible formation mechanism of the Fe3O4 nanocrystals was suggested.