Carbon encapsulated magnetic nanoparticles produced by hydrothermal reaction

Carbon encapsulated magnetic nanoparticles (CEMNs) were synthesized by heating an aqueous glucose solution containing Fe–Au (Au coated Fe nanoparticles) nanoparticles at 160–180 °C for 2 h. This novel hydrothermal approach is not only simple but also provides the surface of CEMNs with functional groups like OH. The formation of carbon encapsulated magnetic nanoparticles was not favored when using pure Fe nanoparticles as cores because of the oxidation of Fe nanoparticles by H₂O during the reaction and, therefore, the surfaces of the naked Fe nanoparticles had to be coated by Au shell in advance. TEM, XRD, XPS and VSM measurments characterized that they were uniform carbon spheres containing some embedded Fe–Au nanoparticles, with a saturation of 14.6 emu/g and the size of the typical product is ∼350 nm.