Synthesis of hierarchical linearly assembled graphitic carbon nanoparticles via catalytic graphitization in SBA-15

Graphitic carbon nanoparticles have received a great deal of attention due to their high electrical conductivity and excellent thermal and chemical stability. Although various synthesis methods have been proposed for the preparation of graphitic carbon nanoparticles, their assembled synthesis has rarely been studied. Here, we report the synthesis of hierarchical, linearly assembled hollow graphitic nanoparticles via catalytic graphitization in SBA-15, hexagonally ordered mesoporous silica. Carbonization of phenol–formaldehyde resin in the presence of impregnated cobalt salts in SBA-15 followed by the removal of the silica template resulted in carbon composites consisting of CMK-3-type amorphous carbon and graphitic carbon nanoparticles. Subsequent chemical oxidation of the amorphous carbon resulted in a bundle of necklace-like carbon nanowires with a length of a few micrometers, where each nanowire consisted of individual ∼50 nm sized hollow graphitic carbon nanoparticles. By contrast, a catalytic graphitization using MCF, mesocellular foam without mesoscopic pore ordering, resulted in randomly assembled graphitic carbon nanoparticles. These findings demonstrate that SBA-15 acted as a macroscopic template for the linear assembly of graphitic carbon nanoparticles during graphitization.