Sustainable Method for the Large-Scale Preparation of Fe₃O₄ Nanocrystals

In this work, a facile synthetic process is reported for the large-scale synthesis of Fe₃O₄ nanocrystals. Thermal decomposition of Fe(acac)₃ (100 g) in 1-hexadecanol produced Fe₃O₄ nanocrystals with well-controlled sizes and morphologies. The nanocrystals were spherically shaped with average diameters of 7.8 ± 0.6, 6.5 ± 0.4, and 5.9 ± 0.2 nm when prepared at 300°C, 270°C, and 250°C, respectively. Mechanisms of crystal formation were elucidated on the basis of gas chromatography-mass spectroscopy analysis, enabling the large-scale preparation of Fe₃O₄ nanocrystals. To provide an environmentally benign route, Fe₃O₄ nanocrystals were prepared with recycled solvent which was recovered from the initial experiment. The resulting porous Fe₃O₄ nanocrystals had larger average sizes than those of the initial nanocrystals. Structural characterization was performed using transmission electron microscopy and powder X-ray diffraction.