Synthesis of β-SiC/SiO2 core-shell nanowires with the assistance of cerium oxide

The beta-SiC/SiO2 core-shell nanowires with the "stem-and-node" structure were synthesized in the presence of cerium oxide by the carbothermal reduction of the starch-SiO2 hybrids gel. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and energy-dispersed X-ray (EDX). The results showed that the nanowires consisted of a 20-35 nm diameter crystalline beta-SiC core wrapped with a 2-5 nm amorphous SiO2 shell, with their lengths up to several micrometers. The axes of nanowires lay along the [111] direction with a clean surface possessing a high density of planar defects. Base on the experimental results, it was suggested that the novel beta-SiC/SiO2 core-shell coaxial nanowires with the "stem-and-node" structure were formed via the Vapor-liquid-solid (VLS) growth mechanism.