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-containing surface functional groups on the surfaces of graphite, glassy carbon, bamboo-like, and hollow-tube multiwalled carbon nanotubes and single-walled carbon nanotubes by chemically labeling them with either an inorganic hexamminechromium(III) complex or organic 1,2-phenylenediamine derivatives. Both types of labels can be observed using cyclic voltammetry or by X-ray photoelectron spectroscopy and used to quantify the numbers and relative distribution of ortho-quinones from other oxygen-containing species on the surface including electroactive para-quinones which are not labeled. Labeling of ortho-quinones with 1,2-phenylenediamine derivatives results in the formation of phenazine-like adducts on the graphitic surface which have a distinct voltammetry particularly from that of the underivatized para-quinones.