Influences of different synthesis conditions on properties of Fe3O4 nanoparticles

Magnetic nanoparticles of Fe3O4 had been fabricated through hydrothermal reaction by using sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as a surfactant and hydrazine hydrate (N2H4·H2O) as a reductant. The influences of different concentrations of AOT and N2H4·H2O on the nanoparticles were investigated; moreover, the different reaction temperatures and time were also analyzed. Their structure and morphology were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FT-IR). Furthermore, magnetic properties of the products were studied by vibrating sample magnetometer (VSM). The crystallite size of the samples was calculated using Debye–Scherrer equation. It was found that the as-prepared nanoparticles had been modified by using surfactant during the synthesis process. The amount of AOT and N2H4·H2O, the reaction temperature and time had effects on the size, the dispersal and the magnetic properties of the particles. The well-dispersed magnetic Fe3O4 nanoparticles with better size distribution could be prepared at 150 °C for 10 h when the concentrations of AOT and N2H4·H2O were 0.10 M and 20% (v/v), respectively. Besides, possible mechanisms related to the effects were also discussed.