One-step synthesis of spontaneously graphitized nanocarbon using cobalt-nanoparticles

Amorphous carbon (a-C) films containing metallic Cobalt nanoparticles (Co NPs) were deposited onto microgrids and SiO 2 /Si substrates by a magnetron sputter-deposition technique at room temperature (RT) using aC target with an attachment of a small Co platelet. Transmission electron microscopy (TEM) with a fast Fourier-transform (FFT) revealed the short-range ordering of the lattice corresponding to graphite (002) between Co NPs in the amorphous C matrix. The 2D peak and graphite (002) peak were clearly observed in Raman spectra and x-ray diffraction (XRD), respectively, for the Co–C films. X-ray photoelectron spectroscopy analyses were used to determine the metallic state of Co NPs and sp 2 graphitization in the film. Thus, the Co NPs exhibited higher catalytic activity in spontaneous graphitization at low-temperature than Ni-NPs prepared under the same conditions. So, the metallic NPs were concluded to be promising as the catalyst for the ultra-low temperature graphitization in the solid-phase reaction.