Synthetic hierarchical nanostructures: growth of carbon nanofibers on microfibers by chemical vapor deposition

In this paper the synthesis of three-dimensional hierarchical nanostructures by pyrolysis of acetylene to grow carbon nanofibers (CNFs) on carbon microfibers (CMFs) and glass microfibers (GMFs) is reported. The morphology and structure of the as-prepared CNFs were studied by scanning electron microscopy and high-resolution transmission electron microscopy. CNFs grown on both substrates typically exhibited two types of morphology: the coil-like CNFs with frequent change in orientation and the relatively straight and long CNFs with parallel graphene sheets. The ethanol pretreatment was effective at improving the yield and distribution of the as-grown CNFs on CMFs, but showed an adverse effect to the CNF growth on GMFs. The influence of different substrates and growth temperatures on CNF morphology and the possible growth mechanism for the observed microstructures was discussed.