Structural study of carbon nanomaterials prepared by chlorination of tungsten carbide and bis(cyclopentadienyl)tungsten dichloride

摘要

Hollow carbon nanobags have been obtained by the chlorination of bis(cyclopentadi-enyl)tungsten dichloride (W(C5H5)2Cl2) at 400 and 900 °C. Transmission electron microscopy images indicate an incipient graphitisation at higher reaction temperatures and an increase in the average dimensions of the particles. When using tungsten carbide (WC) as precursor, carbide-derived carbon has been observed at 900 °C, whereas at lower temperatures core-shell-like structures have been found as intermediate reaction steps. In both type of materials, electron energy-loss spectroscopy shows a very similar sp~2 carbon bonding content (～94). Textural studies show Type 1 adsorption isotherms with surface areas of 1250 and 1320 m~2/g for WC and W(C5H5)2Cl2 respectively at the higher temperature treatment.