Preparation, phase analysis and electrochemistry of magnetite (Fe3O4) and maghemite (γ-Fe2O3) nanoparticles

Magnetite and maghemite superparamagnetic nanoparticles were prepared via co-precipitation synthetic route. The phases of the iron nanoparticles were quantitatively confirmed from their powder X-ray Energy dispersive X-ray spectroscopy (EDS) and high resolution transmission electron microscopy (HRTEM) were used to differentiate both types of iron nanoparticles. Cyclic voltammetry showed that magnetite nanoparticles exhibited one redox couple while maghemite had both a redox couple and an irreversible anodic peak. The results shows that aqueous ammonia was more desirable for the synthesis of narrow sized and mono-phased magnetite nanoparticles. The iron oxides prepared from sodium nanoparticles confirmed the nanoparticles were crystalline. Superparamagnetism of magnetite respectively.