Solventless thermal decomposition of ferrocene as a new approach for one-step synthesis of magnetite nanocubes and nanospheres

Abstract

Magnetite (Fe₃O₄) nanocubes and nanospheres were synthesized by solventless thermal decomposition of various mixtures of ferrocene and polyvinylpyrrolidone (PVP). Magnetite nanocubes were prepared by grinding and mixing solid mixtures of ferrocene and PVP. The mixtures were then annealed at 350 °C for 2 h in a sealed cell. The nanocubes' size was controlled by adjusting the [ferrocene]/[PVP] weight ratio. Increasing the annealing time to 4 h when the [ferrocene]/[PVP] weight ratio was 1 : 5 led to the formation of magnetite nanospheres. The formed nanocubes/spheres exhibit ferromagnetic behavior at room temperature. The magnetite nanocubes/spheres were formed by a CVD reaction through which the ferrocene molecules, which are in the gas phase at the reaction conditions, decomposed to magnetite nanocubes/spheres dispersed in the solid PVP matrix. The described method offers a new simple, single-step process for the preparation of magnetite nanocubes/spheres. This approach will be extended in future work for one-step synthesis of other metal oxide nanocubes/spheres, e.g., ZnO, Bi₂O₃, etc.