Electron paramagnetic resonance investigation of purified catalyst-free single-walled carbon nanotubes.
ACS Nano
; 4(12): 7708-16, 2010 Dec 28.
Article
en En
| MEDLINE
| ID: mdl-21082779
ABSTRACT
Electron paramagnetic resonance of single-walled carbon nanotubes (SWCNTs) has been bedevilled by the presence of paramagnetic impurities. To address this, SWCNTs produced by laser ablation with a nonmagnetic PtRhRe catalyst were purified through a multiple step centrifugation process in order to remove amorphous carbon and catalyst impurities. Centrifugation of a SWCNT solution resulted in sedimentation of carbon nanotube bundles containing clusters of catalyst particles, while isolated nanotubes with reduced catalyst particle content remained in the supernatant. Further ultracentrifugation resulted in highly purified SWCNT samples with a narrow diameter distribution and almost no detectable catalyst particles. Electron paramagnetic resonance (EPR) signals were detected only for samples which contained catalyst particles, with the ultracentrifuged SWCNTs showing no EPR signal at X-band (9.4 GHz) and fields < 0.4 T.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Espectroscopía de Resonancia por Spin del Electrón
/
Nanotubos de Carbono
Idioma:
En
Revista:
ACS Nano
Año:
2010
Tipo del documento:
Article
País de afiliación:
Reino Unido