Size-controlled growth of nanocubic Co3O4 and its catalytic application in CVD synthesis of metal/carbon fibre nano structured composite

Abstract

This Thesis reports an experimental study of the preparations of nanostructured materials. In the first project, a method for synthesizing uniform nanocubic Co3O4 with controllable size was developed. The Co3O4 nanocubes were synthesized by an aqueous salt (NaNO3)-assisted oxidation at 110 A?C. The acid washing technique proved effective in isolating the Co3O4 nanocubes and the size of nanocubes could be well controlled by varying the ageing time. Monodispersed Co3O4 nanocubes as small as 10 nm were prepared. A surface-wrapping growth mechanism of the nanocube was proposed based on the experimental data. In the second project the nanocubic Co3O4 was used as a catalyst precursor in a catalytic chemical vapour deposition synthesis of carbon nanofibres from acetylene. It was found the Co3O4 was reduced and reconstructed in situ to well faceted cobalt metal nodules in carbon nanofibres. The interactive growth mechanism of carbon fibres and cobalt nodules was carefully studied.