▎ 摘　　要

A facile catalyst-free one-step approach for the preparation of carbon nanotubes and graphene sheets at ambient pressure and similar to 230 A degrees C has been developed. Carbon nanotubes and graphene sheets are prepared by reducing tetrachloroethylene with sodium in paraffin oil under reflux. The as-prepared products can be easily purified just by washing with common solvents. No metallic contaminants or other impurities exist in the products. The products show unique optical properties and may find various applications such as optical light attenuators and catalyst supports. This high yield and economical process presents a possible strategy for the large-scale production of carbon nanotubes and graphene sheets for future applications.