Ten-gram scale SiC@SiO2 nanowires: high-yield synthesis towards industrialization, in situ growth mechanism and their peculiar photoluminescence and electromagnetic wave absorption properties.

Abstract

SiC@SiO2 nanowires, as a functional nanocomposite, have attracted widespread attention due to their fascinating performance and broad application prospect. However, the low-cost, high yield preparation of large-scale SiC@SiO2 nanowires is still a bottleneck, which hinders their industrial application. Herein, a carbothermal reduction strategy has been developed to synthesize SiC@SiO2 nanowires, which breaks through the handicap of the traditional growth pattern that uses the aid of a substrate. Systematic characterization results illustrate that the yield of the as-obtained products greatly depends on the heating rate, and ten-gram scale SiC@SiO2 nanowires (∼27.2 g) composed of a cubic β-SiC core and homogeneous amorphous SiO2 coating are achieved under the optimum process parameters. The in situ mechanisms of expansion-insertion-growth and inhibition of expansion-package-obstruction are proposed to rationally interpret the growth process of SiC@SiO2 nanowires and the effect of various heating rates, respectively. Furthermore, the SiC@SiO2 nanowires display violet-blue photoluminescence and electromagnetic wave absorption properties. This study not only provides some beneficial suggestions for the commercial production of SiC@SiO2 nanowires, but also reveals promising applications of SiC@SiO2 nanowires in the optical and electromagnetic shielding fields. Moreover, the developed novel in situ growth mechanism enriches the growth theory of one-dimension nanomaterials and offers inspiration for their industrial-scale production.