The Preparation Of Nano Onion-Like Fullerenes By Explosion And Vacuum Heat-Treatment

As a new member of fullerenes family, nano onion-like fullerenes have shown some potential and promising application. Up to date, there are many some problems in the preparation of nano onion-like fullerenes (a high cost and low yield ). Improvement of the existing methods or invention of new methods to prepare nano onion-like fullerenes is of considerable significance in the theory and in practice.A metal-containing carbonaceous hybid xeregel was fabricated from pitch. And the amorphous carbon-encapsulated metalnanoparticles were then obtained by explosion method, which were transformed into nano onion-like fullerenes (NOLFs) in subsequent vacuum heat-treatment. Structures of samples before heat-treatment and after were characterized by HRTEM and X-ray diffraction and the growth mechanism of NOLFs was discussed. The main conclusion are summarized as follows:1) Aqua Mesophase Pitch can be prepared via oxidating pitch which served as carbon source. The nanoparticles of carbon-encapsulated metal compounds (FeCO3 and Fe7C3) withparticle size of about 50nm were prepared by explosion of metal-containing carbonaceous hybrid xerogel which were produced by adding inorganic metal salts to Aqua Mesophase Pitch. After heat-treatment the particles were transformed into metal encapsulated NOLFs.2) Experimental results revealed that the metal-containing carbonaceous hybid xeregel has stronger explosion ability. The explosion temperature & explosion energy are sensitive to the loading density of inorganic iron salts. The high pressure and temperature induced by explosion are benefited to the forming of the nanoparticles of carbon-encapsulated metal compound (FeCO3 and Fe7C3); During the vacuum heat-treatment, NOLFs werecatalyzed by the Fe7C3 particles; the heat-treatment temperature was dependence of melting point of the encapsulated metal compound.