Facile and ultra large scale synthesis of nearly monodispersed CoFe₂O₄ nanoparticles by a low temperature sol–gel route

Nearly monodispersed cobalt ferrite nanoparticles were synthesized by a low temperature sol–gel route using propylene oxide as a gelation agent. The nanoparticles were obtained by the reaction of FeCl₂ and CoCl₂ in ethanol solution with propylene oxide to form the sol, followed by the boiling of the sol solution. The unique chemistry of this procedure allows the formation of highly homogeneous gel intermediate, resulting in the great reducing of crystallization temperature of ferrites to less than 100 °C without postannealing step. This guarantees the preparation of well defined and non-aggregated ferrite nanoparticles on an ultra-large scale of about 75 g in a single reaction. This large scale synthesis strategy offers important advantages over other conventional routes for the preparation of CoFe₂O₄ nanoparticles, showing the promising application of this route in the industrial production.