Facile co-precipitation synthesis of shape-controlled magnetite nanoparticles

Monodispersed magnetite (Fe3O4) nanoparticles with high saturation magnetization, including nanospheres, nanoneedles and nanocubes, were synthesized by the co-precipitation method. The shape of magnetite nanoparticles was controlled by changing the amount of sodium dodecyl sulfate (SDS) and the particle size was adjusted by the irradiation time of visible light. The Fe3O4 nanospheres, nanoneedles and nanocubes were obtained with the addition of 0 g, 0.1–0.4 g and 0.5–1.0 g SDS, respectively. The particle size of nanospheres, nanoneedles and nanocubes of magnetite was ∼15 nm, 100×12 nm2 (length×width) and ∼50 nm under the irradiation time of 30 min. The phase structure, particle shape and size of the samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The as-prepared magnetite nanoparticles from TEM images exhibited a high level of crystallinity with narrow size distribution and good dispersion. The XRD results showed that all the magnetite nanoparticles were pure Fe3O4 phase with obvious diffraction peaks. The products exhibited the attractive magnetic properties with high saturation magnetization, which were examined by a vibrating sample magnetometer (VSM).