Synthesis of hematite and iron oxyhydroxide nanocrystals by precipitation of Fe³⁺ ions inside oleic acid micelles

Abstract

α-Fe2O3 nanospheres with diameters of 20-40 nm and FeOOH nanorods with diameters of 150-200 nm and lengths of 0.5-1.0 μm were synthesized via hydrolysis of Fe(NO3)3 and FeCl 3 solutions, respectively, in the presence of urea and oleic acid, under reflux at temperature ∼90 °C for 8 h. The molar ratio of Fe 3+ ions and urea were changed until pure phases have been obtained. The key parameter of the synthesis which provides pure hematite and β-FeOOH phases was the pH. The samples were characterized by X-ray powder diffraction, transmission electron microscopy and Mössbauer spectroscopy. © 2013 Elsevier Ltd and Techna Group S.r.l.