Energetic characteristics of highly reactive Si nanoparticles prepared by magnesiothermic reduction of mesoporous SiO2

Abstract

In this study, highly reactive silicon nanoparticles (h-Si) were successfully prepared by an improved magnesiothermic reduction process with ∼ 100 nm mesoporous silica nanoparticles as templates. The prepared h-Si have an average particle size of 18 nm, an active content of 85 %, and a specific surface area of 69.2 m2/g. Meanwhile, the preparation process is simple, green (avoiding the use of HF), and shows a great improvement in the inhibition of side reactions. The energetic characteristics of h-Si were compared with those of commercially available silicon nanoparticles (c-Si) by using ultrasonically mixed KClO4 as the oxidizer. Thermal analysis indicates that h-Si/KClO4 has an advanced reaction onset temperature, increased heat release, and lower reaction activation energy. In constant-volume combustion tests, h-Si/KClO4 shows excellent ignition and combustion characteristics in the fuel-rich state. In addition, electrostatic discharge sensitivity tests indicate that the minimum ignition energy of stoichiometric h-Si/KClO4 exceeds 100 mJ, which is much more insensitive than that of n-Al/KClO4 (∼2 mJ). Overall, h-Si show enhanced reactivity and have attractive advantages in applications where suitable combustion properties and low electrostatic sensitivity are required.