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Fibrous aggregates of single-walled carbon nanohorns (carbon nanobrushes: CNBs) were prepared by CO2 laser ablation of an iron-containing carbon target with rotations under nitrogen atmosphere and ambient pressure. The rotation speed of the target and concentration of iron contained in it were controlled so as to increase the yield of CNBs. As a result, many CNBs were obtained at a rotation speed...
Cores of fibrous aggregates composed of radially assembled graphene-based single-walled carbon nanohorns, named as carbon nanobrushes (CNBs), were observed using electron microscopes. As a result, a carbon nanotube (CNT), probably single-layer structure, exposed from the CNBs was observed. From cross section images of CNBs, three round structures of about 2.5 nm diameters were also observed clearly...
Boron- and nitrogen-codoped single walled carbon nanohorns (BN-SWCNHs) were prepared by CO2 laser ablation of a boron-containing carbon target under nitrogen atmosphere. The structures were spherical SWCNH aggregates containing many graphite-like thin sheets (GLSs), which was different from general SWCNHs. X-ray photoelectron spectra indicated that the doped quantities of boron and nitrogen were about...
Boron neutron capture therapy requires boron carriers that can deliver abundant boron to tumors. To obtain such a carrier, we have prepared boron nitride (BN) containing carbon nanohorn aggregate (CNH) by heating CNHs with ammonia borane at 800°C. The obtained BN-CNH had a C:B:N mole ratio of 5:2:2, as estimated from X-ray photoemission spectroscopy. The nanohorn tubule walls had graphene–BN double...
Photothermal conversion of nanocarbons has potential applications in medical and energy engineering. It is expected that the photothermal conversion of tubular nanocarbons can thermally enhance polymer formation on their surfaces and insides. We show in this report that light irradiation enhanced the catalytic polymerization of caprolactone (CL) on tubular carbon nanohorns, and polycaprolactone (PCL)...
Nitrogen-doped single wall carbon nanohorns (N-SWCNHs) were prepared by CO2 laser ablation of a graphite target under nitrogen atmosphere. X-ray photoelectron spectra showed that the doped nitrogen quantities were about 1.7 and 1.1at.% under nitrogen and nitrogen/Ar mixed atmospheres, respectively. The nitrogen atoms were implicated as the pyridine-like and threefold coordinated sp2 bonding in graphene...
Graphite-like thin sheets (GLSs) contained in globular aggregates of carbon nanohorns have few oxygenated groups; therefore, they are suitable for studying how oxidation can be finely controlled. We found that mild oxidation in GLSs with H 2 O 2 solution at room temperature for 7–28days enabled GLS surface layers to be selectively oxidized, where carboxyl, quinone, carbonyl, and hydroxyl...
The graphite-like thin sheets (GLSs) used in this study were prepared by laser ablation of graphite in argon gas. The obtained GLSs were neat, untouched and free-standing. We discovered a new phenomenon with them: even layer numbers (2, 4, 6, and 8) preferentially formed, and their population decreased as the layer number increased. This suggests a new growth mechanism in which single-layer GLSs bend...
We prepared single-wall carbon nanohorns (SWCNHs) with a high specific surface area and fabricated an electrochemical capacitor electrode with good performance from them. Carbon impurities involved in the as-grown SWCNHs were thoroughly removed and the purified SWCNHs were oxidized to produce holes in them (SWCNHox). The specific surface area was estimated as 1720m 2 /g, the largest surface...
We succeeded in morphology-selective preparation of single-wall carbon nanohorn (SWCNH) aggregates by changing the buffer gas (760Torr) in CO 2 laser ablation of graphite: He for seed type, N 2 , Ar and Ne for dahlia type, and Kr for petal dahlia type. In Xe, aggregates of thin graphene sheets were the major product. The degree of graphitization increased with the mass number of the...
We created holes in single-wall carbon nanohorns (SWCNH) by oxidation (SWCNHox) and investigated how the hole size affected the incorporation of C 60 in SWCNHox and their release from it. The incorporation of C 60 inside SWCNHox first occurred when the holes were opened by oxidation at 475°C. It was followed by a steep increase in the incorporation quantity with increasing oxidation...
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