Simultaneous purification and functionalization of carbon nanotubes using chlorination

Multiwalled carbon nanotubes (MWCNTs) obtained using ethylene as a carbon source and nanocrystalline iron as a catalyst were used as the initial material. The functionalization of MWCNTs was carried out using chlorine in the liquid and gas phase. In the second case, the reaction was conducted in the temperature range from 50 to 450 °C for 2 h. The presence of chlorine species on the surface of chlorinated samples was confirmed by x-ray photoelectron spectroscopy (XPS). A quantitative analysis of metal impurity content was validated by means of thermogravimetric analysis. Better results of metal removal were achieved when the chlorination process was conducted in the gas phase and the ratio of metal in samples amounted from 2.3% to 5.1%.