Preparation of silicon carbide nanotubes by hydrothermal method

Abstract

One-dimensional SiC nanotubes with small diameter without metallic catalysts were prepared under supercritically hydrothermal conditions. The SiC nanotubes were characterized by x-ray diffraction, energy dispersive x-ray spectrum, selected area electron diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and Raman and infrared spectra. The results show that the samples are SiC nanotubes composed with crystalline β-SiC structure and some residual carbon nanoscale grains. The SiC nanotubes with small inner pores have an outer diameter of less than 10nm and length of micrometers. The structures of SiC nanotubes are hollow inner pores, multiwall crystalline SiC layers, and thin amorphous silicon oxide outer layers. The substitution reaction model is proposed to explain the formation of SiC nanotubes. C atoms diffuse into Si nanotubes and Si atoms in Si nanotubes are partially substituted for C atoms by substitution chemical reaction, resulting in the formation of SiC nanotubes.