Interphase synthesis of colloidal magnetic cobalt nanoparticles

A. N. Kudlash¹ - S. A. Vorobyova² - A. I. Lesnikovich²

¹ Department of Chemistry, Belarusian State University, 14 Leningradskaya str., 220030 Minsk, Belarus
² Research Institute for Physical-Chemical Problems, Belarusian State University, 14 Leningradskaya str., 220030 Minsk, Belarus

Abstract
The facilities of one-stage synthesis of magnetic cobalt nanoparticles by the interphase reduction of cobalt oleate (hexane or toluene solution) and sodium borohydride (aqueous or ethanol solution) at room temperature without a soluble polymer as a protective agent have been studied. The resultant cobalt nanoparticles have been concentrated either in non-polar or polar phases as black colloidal solutions. The composition and morphology of the colloid's dispersive phase were investigated by transmission electron microscopy, X-ray analysis and IR-spectroscopy. It has been shown that the dispersive phase of the produced colloidal solutions represents spherical crystal cobalt nanoparticles of {\it fcc} and {\it hcp} structures. Their average size varies from 4 to 7\,nm. In accordance with the IR-spectroscopy results, the stability of the produced metallic nanoparticles was provided by the surfactant obtained as a result of the interphase reaction. Tables 1, Figs 5, Refs 12.