| Popis: |
Magnetic MnO, Co, CoO, and Ni nanoparticles are synthesized by thermal decomposition of metal 2,4-pentanedionates in the presence of oleylamine (OLA), oleic acid (OA), and 1-octadecene (ODE). 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). MnO nanoparticles are always obtained as the reaction is controlled with different temperatures, precursor concentrations, ligand ratios, and reaction time. Only three experimental conditions can produce pure phase CoO and Co nanoparticles. The same three experimental conditions lead to the production of pure phase Ni nanoparticles. Other experimental conditions produce mixture phase nanomaterials. The nanoparticle sizes increase with the increase of reaction temperatures. The influence of reaction precursor concentrations on the sizes of the nanoparticles is also studied. The ratio of ligand OLA to OA is used to control the reaction in terms of nanoparticle sizes. It is observed that the reaction time affects nanoparticle growth. The nanoparticles are studied by XRD, TEM, and magnetic measurements. This work presents a facile method to prepare nanoparticles with different sizes, which provides a fundamental understanding of nanoparticle growth in solution. |
