Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1617146 | Journal of Alloys and Compounds | 2011 | 5 Pages |
dMonodisperse iron oxide nanoparticles were prepared by thermal decomposition of iron carbonyl in octyl ether in the presence of oleic acid. The particle size could be tuned from 7 nm to 25 nm. The dual role of oleic acid as a surfactant and a boiling-point elevating agent was discussed. The impacts of varied reflux conditions were investigated and a new monodisperse mechanism was given. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) were used to study the oxidation states of iron oxide nanoparticles. The evolution of d-spacing values in HRTEM images and SAED patterns demonstrated the transition from γ-Fe2O3 to Fe3O4 with the increasing particle size. Superconducting quantum interference device (SQUID) and vibrating sample magnetometer (VSM) were used to reveal the superparamagnetic behavior of as-synthesized nanoparticles.
► The dual role of oleic acid in capping the nanoparticle and elevating the boiling point was discovered. ► γ-Fe2O3 is the dominant phase of small-sized iron oxide nanoparticles and the proportion of the Fe3O4 component gradually increases with the particle size. ► Using aeration or (CH)3NO made little difference in oxidation state. ► The regulation of the reflux states was found crucial in monodisperse mechanisms.