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

Hollow carbon nanobags have been obtained by the chlorination of bis(cyclopentadienyl)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 sp2 carbon bonding content (∼94%). Textural studies show Type 1 adsorption isotherms with surface areas of 1250 and 1320 m2/g for WC and W(C5H5)2Cl2 respectively at the higher temperature treatment.