高比表面积纳米碳化硅的制备及其表征

Synthesis and Characterization of High Surface Area Nano-silicon Carbide

以柠檬酸为造孔剂,利用硅酸乙酯溶胶-凝胶和碳热还原法制备出了高比表面积的纳米碳化硅(SiC)粉体。用TG、XRD、SEM以及BET分析方法对产品进行了表征,结果表明,添加了柠檬酸得到的SiC粉体比表面积可达到13～62m^2·g^(-1),其大小可由柠檬酸与硅酸乙醇的物质的量比x(x=0～1)来控制;柠檬酸受热分解后留下的孔隙是制备高比表面积SiC的关键所在,当x为0.8,凝胶经1500℃碳热还原反应2h后,得到的产品比表面积高,粒径为100nm。

High specific surface area silicon carbide（SiC） was synthesized using citric acid （CA） as the o p re forming agent by the tetraethoxysilane （TEOS） sol-gel and carbothermal method. TG, XRD, SEM and BET were used to characterize the properties of the specimens, and the results show that the specific surface area of SiC derived from sample added with CA varied from 13 to 62m^2·g^-1, and its value can be controlled with x（x =0 -1 ） ,the mole ratio of CA to TEOS; the pores remained after pyrolysis of CA is the key reason to obtain high specific surface area SiC, and when x is 0.8, the gel can change into high specific surface mea SiC Mter holding at 1500℃ for 2h,and the average size of the product is lOOnm.