Magnetic resonance study of carbon encapsulated Ni nanoparticles

Abstract

Magnetic resonance study of six samples consisting of carbon encapsulated nickel nanoparticles or carbon nanotubes ended with such nickel nanoparticles was carried out at room temperature. Samples of Ni/C were prepared by carburization of nanocrystalline nickel by ethylene (C2H4) and methane (CH4). Hydrocarbons decomposition on nickel nanoparticles was done at temperatures 500, 600 and 700°C. Magnetic resonance spectra of samples designated as CH4/500, CH4/600, CH4/700, C2H4/500, C2H4/600 and C2H4/700 were obtained by Bruker E 500 spectrometer. The integrated intensities of the resonance spectra were correlated with the carburization conditions (temperature, type of hydrocarbon) during samples preparation. A core-shell model of the investigated samples allowed rough estimation of appropriate shell sizes.