title: Laser-induced graphitization of colloidal nanodiamonds for excellent oxygen reduction reaction.
abstract: Graphitized nanodiamonds were conveniently prepared by the laser irradiation of colloidal solution using various solvents. The nanodiamonds were converted into a fully graphitized onion-like structure, which became a cage-like mesoporous structure by the degradation of graphitic layers. Alcohols, acetone, and acetonitrile are more efficient solvents for the graphitization compared to water and hydrocarbons. Therefore the number and morphology of the graphitic layers can be simply controlled by the solvent and laser-irradiation duration. We suggest a graphitization model, in which the photocatalytic oxidation of the solvent accelerates the graphitization of nanodiamonds. The graphitized nanodiamonds were easily doped with the nitrogen and sulfur atoms in a controlled manner. In particular, the spherical graphitic layers were preferentially doped with the pyrrolic nitrogen that enhances remarkably electrocatalytic activity for the oxygen reduction reaction.
authors.affiliation: Department of Chemistry, Korea University, Jochiwon 339-700, Korea. parkjh@korea.ac.kr.
authors.forename: Dong Myung
authors.initials: DM
authors.lastname: Jang
authors.forename: Hyung Soon
authors.initials: HS
authors.lastname: Im
authors.forename: Seung Hyuk
authors.initials: SH
authors.lastname: Back
authors.forename: Kidong
authors.initials: K
authors.lastname: Park
authors.forename: Young Rok
authors.initials: YR
authors.lastname: Lim
authors.forename: Chan Su
authors.initials: CS
authors.lastname: Jung
authors.forename: Jeunghee
authors.initials: J
authors.lastname: Park
authors.forename: Minyung
authors.initials: M
authors.lastname: Lee