Solvothermal synthesis and characterization of nitrogen-enriched carbon-encapsulated nickel nanospheres

Uniform nitrogen-enriched carbon-encapsulated nickel nanospheres were obtained by novel solvothermal method. The phase and morphology of as-prepared sample were characterized by X-ray diffraction (XRD), field-emission scanning electron microcopy (FE-SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that the uniform spheres were made of core–shell structure with nickel core surrounded by 10 nm thickness nitrogen-enriched carbon shell. Elemental analysis (EA) revealed the content of nitrogen in the sample reaching 15 wt% and magnetic measurement showed a ferromagnetic behavior of the sample. On the basis of the experimental results, the growth mechanism of core–shell structural nanospheres was discussed. This solvothermal approach provided facile routine to form nitrogen-enriched nanospheres.