A novel preparation method for γ-Fe2O3 nanoparticles and their characterization

In this paper, γ-Fe2O3 nanoparticles have been prepared by treating the hydroxide precursor in FeCl2 solution. A new transition process induced chemically for preparing oxide nanoparticles is revealed by energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and electron microscopy. The precursor, consisting of a mixture of FeOOH and Mg(OH)2, was synthesized using a common co-precipitation method. After treatment by boiling in FeCl2 solution, γ-Fe2O3 nanoparticles, about 10 nm diameter, were formed. The nanoparticles are highly crystalline and the specific saturation magnetization σs reaches 69.20 emu g−1, which is 90 percent of the value for bulk γ-Fe2O3 and is higher than the value for γ-Fe2O3 nanoparticles of the same size prepared by other methods. The nanoparticles have an inert FeCl2 surface, giving them relatively good chemical stability and dispersivity.

Research highlights
► A new transition process induced chemically for preparing oxide nanoparticles is revealed by energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron (XPS), X-ray diffraction (XRD) and electron microscopy (EM). The analysis results shown that nanoparticles about 10 nm size were prepared by treating the amorphous hydroxide precursor by boiling in FeCl2 solution. The nanoparticles are highly crystalling and the specific saturation magnetization σs reaches 69.20 emu g−1, which is 90 percent of the value for bulk γ-Fe2O3 and is higher than the value for γ-Fe2O3 nanoparticles of the same size prepared by other method.