Figure 4.

XPS C 1s spectra of the pristine MWCNTs and the five chemical species: (1) graphite; (2) sp3 carbons; (3) hydroxyl groups; (4) carbonyl groups; and (5) carboxyl groups

Tseng et al. Nanoscale Research Letters 2008 4:234-239   doi:10.1007/s11671-008-9231-4