title: Theoretical and experimental studies on the carbon-nanotube surface oxidation by nitric acid: interplay between functionalization and vacancy enlargement.
abstract: The nitric acid oxidation of multiwalled carbon nanotubes leading to surface carboxylic groups has been investigated both experimentally and theoretically. The experimental results show that such a reaction involves the initial rapid formation of carbonyl groups, which are then transformed into phenol or carboxylic groups. At room temperature, this reaction takes place on the most reactive carbon atoms. At higher temperatures a different mechanism would operate, as evidenced by the difference in activation energies. Experimental data can be partially related to first-principles calculations, showing a multistep functionalization mechanism. The theoretical aspects of the present article have led us to propose the most efficient pathway leading to carboxylic acid functional groups on the surface. Starting from mono-vacancies, it ends up with the synergistic formation of dangling -COOH groups and the enlargement of the vacancies.
authors.affiliation: Université de Toulouse, INSA, UPS, CNRS, LPCNO, UMR 5215, (IRSAMC), 135 avenue de Rangueil, 31077 Toulouse cedex 4, France.
authors.forename: Iann
authors.initials: I
authors.lastname: Gerber
authors.forename: Mustapha
authors.initials: M
authors.lastname: Oubenali
authors.forename: Revathi
authors.initials: R
authors.lastname: Bacsa
authors.forename: Jérôme
authors.initials: J
authors.lastname: Durand
authors.forename: Alexandra
authors.initials: A
authors.lastname: Gonçalves
authors.forename: M Fernando R
authors.initials: MF
authors.lastname: Pereira
authors.forename: Franck
authors.initials: F
authors.lastname: Jolibois
authors.forename: Lionel
authors.initials: L
authors.lastname: Perrin
authors.forename: Romuald
authors.initials: R
authors.lastname: Poteau
authors.forename: Philippe
authors.initials: P
authors.lastname: Serp