Raman characterization of single-walled nanotubes of various diameters obtained by catalytic disproportionation of CO
Single-walled carbon nanotubes prepared by disproportionation of CO over Co-Mo/SiO 2 catalysts have been characterized by Raman spectroscopy, using several excitation energies. By varying the reaction temperature, different ranges of nanotube diameter were obtained. The average diameter of a single-...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2003 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/63651 |
| Acceso en línea: | http://hdl.handle.net/11336/63651 |
| Access Level: | acceso abierto |
| Palabra clave: | Cobalt Molybdenum Catalyst Metal Nanoparticles Raman Spectroscopy Single Wall Nanotube Diameter Single Wall Nanotube Growth Single Wall Nanotube Production https://purl.org/becyt/ford/2.4 https://purl.org/becyt/ford/2 |
| Sumario: | Single-walled carbon nanotubes prepared by disproportionation of CO over Co-Mo/SiO 2 catalysts have been characterized by Raman spectroscopy, using several excitation energies. By varying the reaction temperature, different ranges of nanotube diameter were obtained. The average diameter of a single-walled nanotube produced at 750°C was 0.9 nm, while it increased up to about 1.5 nm when the synthesis was conducted at 950°C. The analysis of the Raman spectra obtained with a range of laser excitation energies not only gives a definite description of the single-walled nanotubes diameters but also helps differentiate the metallic or semiconducting character of the samples. This analysis can be done by comparing the experimental data with calculated gap energies as a function of nanotube diameter as well as comparing the relative intensity of bands centered at 50-60 cm -1 lower than the tangential G mode. The analysis of this feature, which can be fitted with a Breit-Wigner-Fano line, offers a method for distinguishing between metallic and semiconducting single-walled carbon nanotubes. |
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