Solution-phase decomposition of ferrocene into wüstite-iron oxide core-shell nanoparticles.

We report an improved method for the controlled solvent-phase decomposition of ferrocene into highly crystalline monodisperse iron oxide nanoparticles at relatively low temperatures. Solution-phase decomposition of ferrocene into nanoparticles has received little attention in the literature, due to the percieved stability of ferrocene. However, we synthesised wüstite FeO-iron oxide core-shell nanoparticles by thermally decomposing ferrocene in 1-octadecene solvent and in the presence of oleic acid and oleylamine, as surfactants. We report procedures that provide cubic and spherical core-shell iron oxide nanoparticles whose size (29.3 ± 2.3 nm for spheres, 38.6 ± 6.9 nm for distorted cubes and 23.5 ± 2.4 nm for distorted cubes with concave faces) and shape can be controlled through simple adjustments to reaction parameters. Transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, electron energy-loss spectroscopy and powder X-ray diffraction analysis methods were used to characterise the nanoparticles.

A simple procedure for the production of large ferromagnetic cobalt nanoparticles.

Epsilon cobalt (ε-Co) nanoparticles in a number of octahedral morphologies have been synthesised. The particles are polycrystalline, with sizes in the order of 30 nm. Magnetic studies reveal the particles are ferromagnetic, with a room temperature saturation magnetisation of 131 emu g(-1). Unlike other large cubic ε-Co syntheses, we have not added an additional co-surfactant. Instead, we have modified the heating regime and reaction agitation. This alternative method highlights the complex chemistry associated with the formation of cobalt nanoparticles by thermal decomposition.