Characterising chemical functionality on carbon surfaces

Abstract

This feature article introduces the reader to the surface chemistry and structure of graphitic carbon materials, including carbon nanotubes. Recent work involving the development of dual labels that allow us to selectively and quantitatively label carboxyl and general carbonyl groups (such as quinones, ketones and aldehydes) and to distinguish between ortho- and para-quinone groups is reviewed. In addition, the mechanisms of covalent, chemical derivatisation of these surfaces and the reactive sites towards attack by radical and cationic intermediates are discussed, as well as the interesting effects on the pKa values of organic molecules that attachment to a carbon surface can induce. When combined, the methods described herein allow one to differentiate and explore the chemical functionality and reactive sites on graphitic carbon surfaces

New insight into 4-nitrobenzene diazonium reduction process: Evidence for a grafting step distinct from NO2 electrochemical reactivity

“…The main reason is that the lowest potential applied during the CV was 0 V, thus avoiding the reduction of NO 2 into NHOH group as demonstrated before. Only a little, bad-defined reversible system was observed around 0.27 V on both grafted and unmodified electrodes and was assumed to belong to the quinone redox system often observed on GC after polarization [40][41][42]. The same behavior was obtained when the electrolysis at 0.3 V was performed in acetonitrile containing 2.5 mM NBD.…”

Nickel(ii) tetra-aminophthalocyanine modified MWCNTs as potential nanocomposite materials for the development of supercapacitors

“…In the case of acid pretreated MWCNTs these are likely to correspond to the two-electron, two-proton redox process of surface quinones, which are also introduced as surface oxogroups during acid pretreatment of MWCNTs. [22][23][24] These surface quinones give rise to two small, ill-defined, quasireversible redox waves observed at ca. 0.2 V vs. SCE at low pH, corresponding to both ortho-and para-quinone surface groups.…”

Electrocatalysis of oxygen reduction on multi-walled carbon nanotube supported copper and manganese phthalocyanines in alkaline media

“…The O1s peak is related to the support material and is caused by various carbon-oxygen functionalities on the surface of carbon nanotubes. Identification of several functional groups from the O1s [48,49]. The N1s XPS core-level spectrum of MnPc/MWCNT is presented as inset in Fig.…”