The Studies On Onion-Like Fullerenes Prepared By Arc Discharge Method

As a new member of the fullerene family, nano-onion-like fullerenes have attracted wide attentions and great interests of many scientists in the world, and have been focus of the new materials studies since it was found in 1992. However, the application studies of onion-like fullerenes develop slowly for the lack of effective preparation methods. In this paper, ideal technics parameters of producing nano-onion-like fullerenes were obtained, using arc discharge, by designing rational experiment project.In the experiments, we used cheap N2 as preserving gas, andadjusted gas pressure, discharge current, voltage and so on, to produce the large quantities of onion-like fullerenes. At the same time, we used Fe, Ni , Al as catalysts, and compared their catalyst properties to ascertain the catalyst effects on the yields and qualities of onion-like fullerenes. X-ray diffraction(XRD) and high resolution transmission electron microscope(HRTEM) were used to characterize and analyze the morphologies and microstructure of the products. We discussed the effects of technics parameters such as the pressure of transfer gas, the discharge current and voltage, and the kind of the catalysts, on the formation of onion-like fullerenes during arc discharging. And optimun experimental conditions were obtained : the current is 150~160A, voltage is 25-30V, gas pressure is 0.04MPa. Meanwhile, we found that onion-like fullerenes prepared with Fe as catalyst were pure and highly graphitized.The growth mechanisms of onion-like fullerenes were also discussed in this paper. We found that the temperature and catalystnature both affect the nucleation and growth of onion-like fullerenes. This prepared for the studies on properties and applications of onion-like fullerenes.