水热/超声法合成γ-Fe<sub>2</sub>O<sub>3</sub>纳米空心球及磁性
摘要
Combine the advantages of hydrothermal approach and ultrasonic method, Fe<sub>3</sub>O<sub>4</sub> solid nanospheres with grain sizes of ~15 nm are prepared by hydrothermal approach. Then treat these Fe<sub>3</sub>O<sub>4</sub> solid nanospheres with acid and finally sonicate in ferric nitrate solution, γ-Fe<sub>2</sub>O<sub>3</sub> hollow nanospheres with grain size of ~5 nm are obtained. X-ray diffraction (XRD) and energy dispersive spectrometer (EDS), scanning electron/transmission electron microscopy (SEM/TEM), nitrogen adsorption and pore size distribution (BJH) prove that the sample is high purity γ-Fe<sub>2</sub>O<sub>3</sub> hollow nanospheres with pore structure. Superconducting quantum interference device and stability experiment demonstrate that γ-Fe<sub>2</sub>O<sub>3</sub> hollow nanospheres are superparamagnetism with a high saturation magnetization and chemical stability at room temperature.