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.
Daniele, P., Matteo, A., Mattia, G., Marcello, M., Sanna, S., Filippo, C., et al. (2014). Tracking the Hydrogen Motion in Defective Graphene. JOURNAL OF PHYSICAL CHEMISTRY. C, 118, 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.