Iron-iron oxide core-shell nanoparticles synthesized by laser pyrolysis followed

2019-09-24 07:42:40

core Iron shell laser oxide

责任者: Dumitrache, F.;Morjan, I.;Alexandrescu, R.;Ciupina, V.;Prodan, G.;Voicu, I.;Fleaca, C.;Albu, L.;Savoiu, M.;Sandu, I.;Popovici, E.;Soare, I. 单位: National Institute for Lasers, Plasma and Radiation Physics, 077125 Bucharest, Romania 来源出处: Applied Surface Science,2005,247(1-4):25-31 摘要: Iron-based core-shell nanostructures were synthesized by laser pyrolysis in a two-steps procedure. In a first step, using a cross-flow configuration, the laser radiation was heating a gas phase mixture containing iron pentacarbonyl (vapors) entrained by an ethylene flow, which plays also the role of an energy transfer agent. Secondly, a carefully controlled in situ passivation of the freshly formed pyrophoric iron nanoparticles created a protective iron oxide shell. The produced nanoparticles (22 nm size diameters) with core-shell features were analyzed by TEM, XRD, SAED and Raman spectroscopy. Majoritary iron and gamma iron oxide/magnetite and minoritary carbon phases were identified. In laser pyrolysis experiments in which the reaction temperature was increased, the catalyzed homogeneous nucleation and growth of carbon nanotubes in the gas phase was observed and is presented here for the first time. © 2005 Elsevier B.V. All rights reserved. 关键词: Nanostructured materials;Iron powder;Synthesis (chemical);Laser beam effects;Pyrolysis;Oxidation;Energy transfer;Passivation;Carbon nanotubes;Transmission electron microscopy;X ray diffraction analysis;Raman spectroscopy;Laser pyrolysis;Iron core oxide shell nanocomposites;Gas phase mixtures;Environmental instability