MnO, Co and Ni Nanoparticle Synthesis by Oleylamie and Oleic Acid

Abstract

Background: Magnetic nanoparticles are attracting much attention toward easy operation and size controllable synthesis methods. We develop a method to synthesize MnO, Co, CoO, and Ni nanoparticles by thermal decomposition of metal 2,4-pentanedionates in the presence of oleylamine (OLA), oleic acid (OA), and 1-octadecene (ODE). Methods: Similar experimental conditions are used to prepare nanoparticles except for the metal starting materials (manganese 2,4-pentanedionate, nickel 2,4-pentanedionate, and cobalt 2,4- pentanedionate), leading to different products. For the manganese 2,4-pentanedionate starting material, MnO nanoparticles are always obtained as the reaction is controlled with different temperatures, precursor concentrations, ligand ratios, and reaction time. For the cobalt 2,4- pentanedionate starting material, only three experimental conditions can produce pure phase CoO and Co nanoparticles. For the nickel 2,4-pentanedionate starting material, only three experimental conditions lead to the production of pure phase Ni nanoparticles. Results: The nanoparticle sizes increase with the increase of reaction temperatures. It is observed that the reaction time affects nanoparticle growth. The nanoparticles are studied by XRD, TEM, and magnetic measurements. Conclusion: This work presents a facile method to prepare nanoparticles with different sizes, which provides a fundamental understanding of nanoparticle growth in solution.