Highly structured, biomorphous β-SiC with high specific surface area from Equisetaceae

Abstract

Mesoporous, highly structured silicon carbide (β-SiC) was synthesised from renewable plant materials (two Equisetaceae species) in a one-step carbothermal process at remarkably low temperatures down to 1200 °C. The SiC precursor is a silicon–carbon mixture with finely dispersed carbon prepared by pyrolysis of the organic plant matrix. Yields are 3 to 100% (ω_Si/Si related to the silicon deposited in the plant material), depending on reaction temperature and time. IR spectroscopy, X-ray diffraction, and nitrogen sorption prove the formation of high-purity β-SiC with minor inorganic impurities after purification and a high specific surface area of up to 660 m² g⁻¹. Scanning electron microscopy shows that the plant morphology is maintained in the final SiC. Sedimentation analysis finds a mean particle size (diameters d₅₀) of 20 μm.