Bulk defective graphene produced by thermal exfoliation of graphite oxide was treated under H2 and investigated with X-ray photoemission spectroscopy, neutron spectroscopy, and solid state nuclear magnetic resonance. Graphene defects appear effective in dissociating H2 molecule and in promoting H covalent absorption on the carbon backbone. Measured generalized phonon density of states shows the presence of localized peaks ascribed to C−H bending modes already in pristine graphene, whose intensities enhance when samples are treated under H2 at 1273 K. However, 1H NMR evidences a thermally activated dynamics with a correlation time of a few microseconds assigned to a part of H atoms bound onto the graphene plane. These findings point toward a diffusive dynamics of the hydrogen chemically bound to graphene sheets, already active at room temperature.

Tracking the Hydrogen Motion in Defective Graphene / Pontiroli, Daniele; Aramini, Matteo; Gaboardi, Mattia; Mazzani, Marcello; Sanna, Samuele; Caracciolo, Filippo; Carretta, Pietro; Cavallari, Chiara; Rols, Stephane; Tatti, Roberta; Aversa, Lucrezia; Verucchi, Roberto; Riccò, Mauro. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - 118:13(2014), pp. 7110-7116. [10.1021/jp408339m]

Tracking the Hydrogen Motion in Defective Graphene

PONTIROLI, Daniele;ARAMINI, Matteo;GABOARDI, Mattia Gianandrea;MAZZANI, Marcello;RICCO', Mauro
2014

Abstract

Bulk defective graphene produced by thermal exfoliation of graphite oxide was treated under H2 and investigated with X-ray photoemission spectroscopy, neutron spectroscopy, and solid state nuclear magnetic resonance. Graphene defects appear effective in dissociating H2 molecule and in promoting H covalent absorption on the carbon backbone. Measured generalized phonon density of states shows the presence of localized peaks ascribed to C−H bending modes already in pristine graphene, whose intensities enhance when samples are treated under H2 at 1273 K. However, 1H NMR evidences a thermally activated dynamics with a correlation time of a few microseconds assigned to a part of H atoms bound onto the graphene plane. These findings point toward a diffusive dynamics of the hydrogen chemically bound to graphene sheets, already active at room temperature.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11381/2787076
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