Synthesis of Highly Nanoporous β-Silicon Carbide from Corn Stover and Sandstone

Porous β-Silicon carbide (β-SiC) is an important ceramic material due to its superior properties, such as high surface area, excellent chemical and mechanical stability, and high resistance toward oxidation and corrosion. In this study, inexpensive and easily obtained corn stover and sandstone were used as the carbon and silicon sources, respectively, and porous β-SiC was effectively synthesized with a high yield. The synthesized β-SiC was characterized by XRD, Raman, SEM, TEM, and TGA, and the gaseous products were also analyzed with an integrated furnace-MS system. The results show that the produced β-SiC exhibited a nanostructure that followed the graphitic carbon template derived from the pyrolysis of the corn stover. The surface area as high as 397 m2/g, the pore volume of 0.4 cm3/g, as well as the majority pore diameters of 3-6 nm were achieved. CO and CO2 were released during the reaction between vaporized SiO and graphite. The effect of temperature in the range of 1000 to 1700 °C was also studied, and the results point to a strong dependence between the process temperature and the yield and density of β-SiC. Also, the possible mechanism of synthesized β-SiC was proposed and confirmed with experimental results. This study provides a simple and an eco-friendly carbothermal reduction approach to produce nanoporous β-SiC with agriculture waste and sandstone, which could help establish the green economy in the US.