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Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 9: Graphene I: Structure and Growth (joint session O/TT)

TT 9.7: Vortrag

Montag, 1. April 2019, 12:15–12:30, H24

The role of the curvature of graphitic materials in the oxygen adoption reactionJakob Hauns, Julian Wüst, Jürgen Weippert, Regina Fischer, Frank Hennrich, Dmitry Strelnikov, •Artur Böttcher, and Manfred M. Kappes — Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany

The capability of graphitic materials to bind atomic oxygen has been studied under ultrahigh vacuum conditions by monitoring the oxygen-induced evolution of the XPS-O1s, -C1s and the valence band states, UPS-VB. Three groups of solid films were investigated: HOPG (planar graphene sheet), felts of metallicity-sorted single walled carbon nanotubes S-, M-SWCNTs and solid C60 films. The monodispersed materials chosen here differ by the curvature C of the graphene layers. In order to quantify the role of strained C-C-C bonds in the oxidation pathway exactly the same oxidation procedure has been applied to all graphitic materials. The VB-DOS profiles measured for oxidized films differ clearly by their oxygen-derived bands and the work functions. The evolution of the XPS-O1s and -C1s states indicate that whereas the oxidation of planar graphene sheets proceeds via epoxy species [1], ether functionalities dominate the oxidative scenario of the curved surfaces of SWCNT and C60. The yield for the initial oxygen-adoption reaction for all curved surfaces is significantly higher than that measured for planar graphene sheets. This finding stresses the unique role of the strained -C-C-C- bonds which facilitate the formation of ether functionalities. [1] A. Barinov, et al. J. Phys. Chem. C 2009, 113, 9009.

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