Solvothermal Synthesis of Tunable Electroactive Magnetite Nanorods by Controlling the Side Reaction

A solvothermal process was designed to synthesize magnetite (Fe3O4) nanorods using iron pentacarbonyl (Fe(CO)5), oleic acid, and hexadecylamine as raw materials. In the preparation process, Fe(CO)5 was first decomposed and oxidized to form FeO. Meanwhile, Fe(CO)5 reacted with oleic acid to form iron oleate. In the system water derived from the reaction between oleic acid and hexadecylamine resulted in the hydrolysis of iron oleate to form the initial Fe3O4 nanorods. In the following process, the dissolution of FeO and decomposition of residual Fe(CO)5 as well as the hydrolysis of iron oleate provided the source for the growth of Fe3O4 nanorods, which led to the enlargement of the particles with time. By adjusting the reaction time or the amount of the added hexadecylamine, the length of uniform nanorods could be tuned from 63 to 140 nm. Furthermore, the as-prepared Fe3O4 nanorods showed excellent performance in electrochemical property and exhibited different magnetic property from spherical nanoparticles and nanoplates for their shape anisotropy.