Water Oxidation of Multi-Walled Carbon Nanotubes under Moderate Industrial Condition

The functionalization of Multi-walled carbon nanotubes (MWNTs) using water vapor at temperature of 600 degrees C-1000 degrees C is reported in this paper. Raman spectra and X-ray photoelectron spectrum (XPS) were used to characterize the products. The XPS spectra showed the existence of oxygen atoms in the functionalized MWNTs in the form of -C-O, -C=O groups, and the content of Oxygen atoms in the products can be raised from 2.2at.% to 4.7at.% as the heating temperature rise from 600 degrees C to 800 degrees C. The rising of peaks corresponding to the -C=O bond and the diminishing of peaks corresponding to the -C-O bond as the treating temperature rising showed the thermal enhanced oxidizing ability of water molecules, while little changes in the intensity of peaks in the D and 2D band with respect to the peak at G band in the Raman spectra showed that the process induced little defects to the MWNTs. Our experiments also shows that when the temperature are higher than 800 degrees C, more defect would be induced and no MWNTs would be left when treated under 1000 degrees C. Compared to the traditional solvent approaches, method shown in this paper shows the advantage of environmental friendly and keeping the morphology of MWNT aggregations unchanged.