During the oxidation, oxygen-containing functional groups, including Cdouble bond; length as m-dashO/COOH, OH, and Csingle bondOsingle bondC, were introduced at the edge and on the basal plane, as shown in the Fourier transform infrared (FTIR) spectrum (Fig. 2). The deoxidization is further confirmed by the changes in the FTIR. After the reduction treatment, the strongest vibrational absorption band of Cdouble bond; length as m-dashO/COOH at 1720 cm−1 became very weak and the vibration band of epoxy groups at 1097 cm−1 disappeared (Fig. 2).