Confined Synthesis and Properties of Porous Silicon from Silica Aerogel Templates by Magnesiothermic Reduction

Novel nanoporous silicon was successfully converted from SiO2 aerogels by a template-confined magnesiothermic reduction at low temperature (650 °C) based on a gas-solid reaction. The composition, crystal structure, morphology, and pore structure of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett- Teller (BET) surface area analysis. Their optical and electrochemical properties were also investigated. The results indicated that the products consisted of nanocrystalline silicon, retained a morphology similar to that of the original templates, and possessed a specific surface area as high as 602 m 2 ·g - 1 . They also showed red photoluminescence at room temperature and had a high capacity and good Li-ion insertion/extraction properties for use in lithium ion batteries. (Article)