Formation of Co filled carbon nanocapsules by metal-template graphitization of diamond nanoparticles

Abstract

Co filled carbon nanocapsules, which are formed by a heat treatment of the mixture of Co and diamond nanoparticles, have been studied by in situ transmission electron microscopy (TEM), x-ray diffraction, and Raman spectroscopy. Raman studies show that the heat treatment reduces the surface native oxide (Co3O4) of Co nanoparticles. The reduction is accompanied by graphitization of diamond nanoparticles, indicating that diamond nanoparticles being in contact with the metallic Co are transformed into graphitic coating. The in situ TEM studies show that the graphitic coating is formed in the heating process, not in the cooling process. Furthermore, once the coating is completed, the number of the graphitic layers is almost constant on further heating and cooling. These results allow us to conclude that metallic Co particles simply act as templates for graphitic coating.

Solid‐State Microwave‐Arcing‐Induced Formation and Surface Functionalization of Core/Shell Metal/Carbon Nanoparticles

“…Many methods have been developed in attempt to produce a metal nanoparticle core wrapped with well‐graphitized carbon shells in a pure form without simultaneous formation of carbon nanotubes. These methods include thermal treatment of carbon soot,8 thermal pyrolysis of organometallics9, 10 and nanodiamonds,11 or thermal pyrolysis of metal nanoparticles mixed with polymers,12 starch,13 or ionic liquids 14. In many cases, nanoparticles have carbon shells with amorphous structures or are minor products in the carbon soot except in a few cases 2, 3, 15–17.…”

Processing and properties of composite magnetic powders containing Co nanoparticles in polymeric matrix

“…of works [1][2][3][4][5][6][7][8][9][10]. However, the general conclusion is that their properties strongly depend on the processing method and parameters applied.…”

Formation of promising Co–C nanocompositions

“…Recently, diamond also was tested for the synthesis of Co-C composition by mechanical mixing and subsequent high-temperature annealing of carbon and metal nanoparticles. 10,11 Here we report the synthesis of Co-C nanocomposition by using simultaneous deposition of cobalt and fullerene as initial components. Such a choice was founded on a desire to achieve the separation of Co nanocrystals by C 60 molecules, which can lead to a structure with advanced magnetic and electronic properties.…”