Preparation of fullerenes using carbon rods manufactured from Chinese hardcoals

We report a feasibility study of producing fullerenes (C-60 and C-70) using carbon rods manufactured from Chinese coal which is one of the cheapest na tural resources of carbon. A DC are method is employed using coal-derived c arbon rods as electrode materials. The carbon rods are prepared from seven typical Chinese hard coals including bituminous coals and anthracite. The r esults show that all Chinese coals tested can be used to produce significan t quantities of fullerenes. Their yields are strongly affected by the metho ds of preparing carbon electrodes and the parameters of the are process, wh ich are directly related to the coal properties and characteristics. Our re sults show that the two-step carbonisation method is significantly better t han the one-step hot-pressing method with regard to the fullerene yields, a s such the two-step method is recommended for fullerenes production from Ch inese coals. It is found that the fullerene yield increases as the carbon c ontent in coal increases and as ash content in coal decreases. This suggest s that the mineral matter in coals could somehow inhibit the fullerenes pro duction. An interesting linear relationship between the C-60/C-70 ratios an d the volatile matter content in Chinese coals is also noted, (C) 2000 Else vier Science Ltd. All rights reserved.