Growth mechanism of silica nanowires without a metal catalyst via oxyacetylene torch ablation

In this paper, for the first time, silica nanowires (SiONWs) were synthesized without a metal catalyst via ablation of SiC-containing coating under oxyacetylene torch. The growth mechanism of silica nanowires was discussed by using a developed vapor-liquid-solid (VLS) and oxide-assisted growth (OAG) model. Silica nanoparticles as a growth catalyst provided silicon and oxygen atoms for the formation of the nanowires and served as a growth site as well. In the center region, silica nanowires with an even diameter of 150 nm and a length up to more than 100 μm formed during the cooling process. In the outer region, silica nanowires were synthesized during the ablation process and finally grew into a cauliflower-like silica layer.