Structure and electronic states of single-wall carbon nanohorns prepared under nitrogen atmosphere

Morphological changes in carbon nanohorns under stress: a combined Raman spectroscopy and TEM study

“…33,49 Regarding the intensities variations we observe in Figure 7c that the ratio IG/ID decreases from 0.85 to 0.60 after consecutive stress cycles, thus -10-indicating significant changes in the ratio double (C=C) to single (C-C) bonding in the sample. 43,44 The above findings are supported by the TEM and HRTEM images of the recovered samples shown in Figure 8. After one stress cycle, a transition from dahlia-like to bud-like carbon nanohorns takes place (Figure 8a-e).…”

“…In other words, such ratio establishes some sort of hybridization scale for the material under study, being infinite for HOPG graphite and zero for diamond. 43,44 Our results reveal an increase in C=C bonds when the CNHs samples are subjected to large compression. Having into account the evolution with stress of the Raman spectra, as measured by the FWHMs and relative band intensities, we conclude that CNHs turn into a carbonaceous sp 2 structure upon compression.…”

Monolithic Solid Based on Single-Walled Carbon Nanohorns: Preparation, Characterization, and Practical Evaluation as a Sorbent

“…Figure 6 A shows the Raman spectra of pristine SWNHs (1), that of SWNHs dispersed in chloroform followed by a rapid evaporation of the solvent with (3) and without (2) the previous sonication step, and the SWNH-monolith prepared as previously described (4). As can be seen, the Raman spectrum of the pristine SWNHs at room conditions exhibits the characteristic bands typical of sp 2 defected carbon materials, i.e., the G band (~1589 cm −1 ) associated with the double bonds between the carbon atoms (C=C), which originates from in-plane E2g stretching vibrations in the sp 2 bonded carbon atoms [ 31 ], and the D band (~1350 cm −1 ), assigned to A1g-symmetry modes [ 32 ], which is related to the introduction of pentagons and heptagons resulting in the typical conical-shape of SWNHs, as well as with the presence of single-bonding sp 3 carbon atoms (C–C) [ 26 , 33 ].…”

Review—Single-Walled Carbon Nanohorn-Based Dye-Sensitized Solar Cells

“…In fact, they are produced at scales of around 1 kg day −1 . 24,25 Complementary methods comprise pulsed arc discharge, 26 torch arc in open air, 27 and cavity arc jet in open air. 28 Regarding spectroscopy, the Raman spectrum of SWCNHs reveals graphitic and amorphous carbon-like features.…”

“…The I D / I G ratio increased from ∼0.9 to 1.22 for pristine and ox-SWCNHs, respectively. 25 ox-SWCNH dispersions in ethanol were spray-coated under a N 2 stream onto FTOs and subsequently sintered at 400…”