article
Morphology and composition tailoring of Co x Fe3 − xO4 nanoparticles
Registro en:
1388-0764
1572-896X
10.1007/s11051-017-4097-y
Autor
Medeiros, I. A. Fernandes
Madigou, V.
Moriyama, André Luis Lopes
Souza, C. Pereira
Leroux, Christine
Resumen
Nano-octahedra of cobalt ferrite Co x Fe3 − xO4 (1 ≤ x < 2), with a broad size distribution around 15–20 nm, were synthesized by a hydrothermal method using nitrates as precursors. For the first time, single-phased nano-octahedra of cobalt-rich ferrite Co x Fe3 − xO4 (x = 1.5) were synthesized. The nano-octahedra are crystallized in a normal spinel structure, with tetrahedral sites occupied by Co2+. This specific octahedral shape was obtained with anionic, cationic, and nonionic surfactants. The nature of the surfactant influenced the chemical composition of the powder and the size of the nano-octahedra. The {100} truncation of the octahedra is more pronounced for the small particles. For the first time, single-phased nanoparticles with as much as x = 1.8 cobalt were synthesized with ethylene glycol as solvent. These nanoparticles, around 8 nm in size, have no specific shape and possess a lacunar spinel structure similar to maghemite. The samples were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy 2027-12