Differentiating between ortho- and para-quinone surface groups on graphite, glassy carbon, and carbon nanotubes using organic and inorganic voltammetric and X-ray photoelectron spectroscopy labels

Ortho-Quinones can be differentiated from other oxygen-contg. surface functional groups on the surfaces of graphite, glassy C, bamboo-like, and hollow-tube multiwalled C nanotubes and single-walled C nanotubes by chem. labeling them with either an inorg. hexaamminechromium(III) complex or org. 1,2-phenylenediamine derivs. Both types of labels can be obsd. using cyclic voltammetry or by XPS and used to quantify the nos. and relative distribution of ortho-quinones from other oxygen-contg. species on the surface including electroactive para-quinones which are not labeled. Labeling of ortho-quinones with 1,2-phenylenediamine derivs. gave phenazine-like adducts on the graphitic surface which have a distinct voltammetry particularly from that of the underivatized para-quinones. [on SciFinder(R)]