Hierarchically structured polymer-derived ceramic fibers by electrospinning and catalyst-assisted pyrolysis

Hierarchically structured polymer-derived ceramic fibers were successfully produced by electrospinning a commercially available preceramic polymer to which a cobalt-based catalyst precursor was added, followed by pyrolysis in nitrogen at temperatures ranging from 1250 to 1400 °C. The nanowires formed via the vapor–liquid–solid (VLS) mechanism, involving the reaction of SiO and CO gases, generated from the decomposition of the polymer-derived-ceramic at high temperature, with the heating atmosphere assisted by the presence of nano-sized CoSi droplets. The main crystalline phase for the nanowires was Si3N4 below 1350 °C, and Si2N2O at 1400 °C, and the amount of nanowires increased with increasing heating temperature. Hierarchically structured fiber mats possessed a higher specific surface area (14.45 m2/g) than that of a sample produced without the cobalt catalyst (4.37 m2/g).