Synthesis of with high specific surface area β-SiC using starch as carbon source

The precursor of silicon carbide (SiC) was obtained by sol-gel methods in which used tetraethoxysilane as silicon source and starch as carbon source,and then the oxalic acid and nickel nitrate were added respectively as catalyst for hydrolysis and polymeration reactions. The obtained precursor was used to prepare SiC by carbothermal reduction in the Ar flow. The samples were characterized by X-ray diffraction,Fourier transform infrared (FTIR) spectroscopy,scanning electron microscope,transmission electron microscope,and low-temperature nitrogen adsorption-desorption measurement. The results showed that the carbothermal temperature for synthesizing SiC needed to be at 1450℃ when the nickel nitrate was employed in the precursor. At this temperature,the obtained sample is composed of agglomerated regular grains with size ranging from 40-60nm and has a high specific surface area of 127.5m2/g and the main pore diametre size center at 4.2 and 10.6nm.