Three-dimensional rice husk-originated mesoporous silicon and its electrical properties

Abstract

A facile and cost-effective process to synthesize nanostructured silicon from rice husk-originated silica is introduced. Rice husk was acid-washed and then calcined at various temperatures in the range of 600–900 °C. Nanostructured silicon was obtained through magnesiothermic reduction process of SiO2. Products of the magnesiothermic process, elemental silicon together with magnesia and magnesium silicate, were subjected to leaching to remove the latter two phases. Based on XRD and XRF results, nanometric silica powder obtained after 3 h calcination at 700 °C was selected for further processing. After reduction process, the formation of a three-dimensional silicon skeleton 70–90 nm in thickness with the specific surface area of 53.02 m2/g was confirmed through HRTEM, SEM and BET observations, in agreement with X-ray pattern. The electrical response of the silicon-based electrode was measured to be 0.0023 Ω m, indicating the employed synthesis route as a promising one for electrode fabrication.