Structural features and magnetic property of nano-sized transition metal dispersed carbons from naphthalene by pressure

Abstract

The transition metal nanoparticle dispersed carbon materials were synthesized by co-carbonization of naphthalene with transition metal compounds, i.e., ferrocene, cobalt acetate and nickel acetate at 540 °C for 6 h under autogenous pressure. The morphologies, structural features and magnetic properties of these metal/carbon nanomaterials were compared by means of SEM, TEM, XRD and VSM measurements. It was found that, coalescent spherulites with uniform diameters from 2 μm to 10 μm were obtained via the co-carbonization of naphthalene and transition metal compounds. The metals mainly exist in the form of elementary metal particles with the size from several nanometers to 300 nm. The Fe particles were encapsulated by carbon layers with well-ordered arrangement to form encapsualtion. Otherwise some of Ni species showed the nanorod morphology coating by carbon layers. The formation mechanisms of these metal/carbon nanomaterials were briefly discussed. The magnetization curves of these materials at room temperature exhibited the characteristics of superparamagnetism response.