Large-Scale Synthesis and Mechanism of β-SiC Nanoparticles from Rice Husks by Low-Temperature Magnesiothermic Reduction

Silicon carbide (SiC) nanomaterials have many applications in semiconductor, refractories, functional ceramics, and composite reinforcement due to their unique chemical and physical properties. However, large-scale and cost-effective synthesis of SiC nanomaterials at a low temperature is still challenging. Herein, a low-temperature and scalable process to produce β-phase SiC nanoparticles from rice husks (RHs) by magnesiothermic reduction (MR) at a relative low temperature of 600 °C is described. The SiC nanoparticles could inherit the morphology of biogenetic nano-SiO 2 in RHs with a size of about 20–30 nm. The MR reaction mechanism and role of intermediate species are investigated. The result shows that SiO 2 is first reduced to Mg 2 Si in the rapid exothermic process and the intermediate product, Mg 2 Si, further reacts with residual SiO 2 and C to produce SiC. Moreover, the SiC shows considerable electromagnetic wave absorption with a minimum reflection loss of −5.88 dB and reflection loss bandwidth < −5 dB of 1.78 GHz. This paper provides a large-scale, cost-effective, environmental friendly, and sustainable process to produce high-quality β-phase SiC nanoparticles from biomass at a low temperature, which is applicable to functional ceramics and optoelectronics.