Bulk defective graphene produced by thermal exfoliation of graphite oxide was treated under H-2 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, H-1 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 e, bound to graphene sheets, already active at room temperature.
Tracking the Hydrogen Motion in Defective Graphene / Daniele, Pontiroli; Matteo, Aramini; Mattia, Gaboardi; Marcello, Mazzani; Sanna, Samuele; Filippo, Caracciolo; Pietro, Carretta; Chiara, Cavallari; Stephane, Rols; Roberta, Tatti; Lucrezia, Aversa; Roberto, Verucchi; Mauro, Riccò. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - STAMPA. - 118:(2014), pp. 7110-7116. [10.1021/jp408339m]
Tracking the Hydrogen Motion in Defective Graphene
SANNA, SAMUELE;
2014
Abstract
Bulk defective graphene produced by thermal exfoliation of graphite oxide was treated under H-2 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, H-1 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 e, bound to graphene sheets, already active at room temperature.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.