Synthesis of nano onion-like fullerenes by chemical vapor deposition using an iron catalyst supported on sodium chloride

摘要

Nano-carbon materials were synthesized by the catalytic decomposition of acetylene at 420 A degrees C using iron supported on sodium chloride as catalyst. The catalysts contain about 0.3, 1.6, 3.3, and 5.2 wt% iron. The samples were examined by scanning and transmission electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The results show that nano onion-like fullerenes (NOLFs) surrounding an Fe(3)C core were obtained using the catalyst containing 0.3 wt% iron. These had a structure of stacked graphitic fragments, with diameters in the range 15-50 nm. When the product was further heat treated under vacuum at 1,100 A degrees C, NOLFs with a clear concentric graphitic layer structure were obtained. The growth mechanism of NOLFs encapsulating metallic cores is suggested to be in accordance with a vapor-solid growth model.