Fe 3 O 4 nanoparticles were prepared from a salt comprising a tetrachloroferrate anion and a methyltrioctylammonium cation in toluene using ethylenediamine as a reductant and pyridine-N-oxide as an oxygen donor and an oxidant. The X-ray diffraction (XRD)analysis, X-ray photoelectron spectroscopy (XPS)and Raman spectroscopy showed that the product was Fe 3 O 4 . Water content measurement with a Karl Fischer moisture meter showed the presence of only a small amount of water in the present system, indicating a limited contribution of water to the formation of Fe 3 O 4 nanoparticles. The Fe 3 O 4 nanoparticle size based on transmission electron microscopy (TEM)observation was approximately 10–30 nm, a result consistent with the crystallite diameter estimated by Scherrer's equation (15.7 nm). A possible reaction mechanism involves the reduction of Fe 3+ to Fe 2+ by ethylenediamine, coordination of both ethylenediamine and pyridine-N-oxide to Fe 2+ , and oxidation of a part of Fe 2+ , leading to a mixed-valence iron-oxygen network, which was a precursor of Fe 3 O 4 nanoparticles. As concerns magnetic properties, saturation magnetization of the product was 57 emu g −1 . Both the coercivity and remanent magnetization were nearly zero and the similar decreases in magnetization were observed above the blocking temperature in the zero-field-cooled and field-cooled curves, results indicating the formation of superparamagnetic Fe 3 O 4 nanoparticles.
|ジャーナル||Solid State Sciences|
|出版物ステータス||Published - 2019 6 1|
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics