A new approach was developed to obtain onion-like carbon-encapsulated cobalt carbide(Co3C) core/shell nanoparticles (NPs) by the laser ablation of cobalt in acetone. TEM observation reveals thatthe Co3C core is encapsulated by graphitized carbon layers. The number of carbon layersshows certain relationship with the size of the core Co3C NPs. The as-derived core/shellNPs presents unique superparamagnetic property and excitation wavelength-dependentﬂuorescence. The formation of the carbide and carbon layer can be explained by thelaser-induced catalytic cracking of the carbon-rich precursor, acetone molecules. The formation of the carbide and carbon layers has beenexplained by the laser-induced catalytic cracking of the acetone molecules. Thesupersaturated carbon atoms in carbide core tend to be excluded and automatically growas carbon layers during the subsequent rapid quenching process.Thisstrategy to prepare such core/shell structure may be highlydesirable for optical devices and electromagnetic waveabsorbers, especially biomedical application thanks to theirclean surface.
Hemin Zhang, Changhao Liang*, Jun Liu, Zhenfei Tian, Guosheng Shao, The formation of onion-like carbon-encapsulated cobaltcarbide core/shell nanoparticles by the laser ablation ofmetallic cobalt in acetone.
Carbon, 2013, 55, 108-115.
Figure 1.(a) and (b): Illustration for the formation process of Co3C/OLC core/shell NPs; (c): images of Co3C/OLC with different sizes; (d) the corresponding SAED pattern of Co3C/OLC core/shell NPs.
Figure 2.(a) Magnetization versus applied field for Co3C/OLC NPs; (b) PL spectra of Co3C/OLC NPs under the different excitation wavelengths.