Synthesis of spherical cobalt oxide nanoparticles by a polyol method

Abstract

We report the synthesis of spherical cobalt oxide nanoparticles by a polyol method. To obtain spherical nanoparticles, water, polyvinylpyrrolidone (PVP), and cobalt acetate tetrahydrate were mixed in diethylene glycol and refluxed at 200°C. Spherical particles were not obtained in the absence of water or PVP, or when the mixture was refluxed at 180°C. The spherical nanoparticles were found to be composed of cobalt (II) oxide (CoO) with a small amount of cobalt oxyhydroxide (CoOOH). The synthesized spherical nanoparticles had good dispersibility in water, and Fourier transform infrared spectroscopy and thermogravimetry-differential thermal analysis measurements indicated that the nanoparticles had a core–shell structure, with a core of CoO and a polymer shell.