HRTEM studies of Y-junction bamboo-like CN-nanotubes
| Autor: | D. V. Batov, I. A. Perezhogin, E. V. Polyakov, V. D. Blank, B. A. Kulnitskiy |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Materials science
Mullite Carbon nanotube Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Branching (polymer chemistry) Catalysis law.invention Condensed Matter::Materials Science Chemical engineering law Transmission electron microscopy Graphite High-resolution transmission electron microscopy Joule heating |
| Zdroj: | EMC 2008 14th European Microscopy Congress 1–5 September 2008, Aachen, Germany ISBN: 9783540852254 |
| DOI: | 10.1007/978-3-540-85226-1_90 |
| Popis: | Carbon branched structures are of interest because of their novel functionality and possible applications. Seamless junctions between carbon nanotubes (CNT) are obtained due to the topological defects (i. e. pentagons, heptagons, octagons, etc.) in the hexagonal lattice. In order to obtain multiwall Y-junction bamboo-like CNx nanotubes we use a technique of resistive heating of graphite in a water-cooled hot isostatic pressure apparatus (HIP). Argon-nitrogen mixture (with molar ratio 1:2.5) was used as a gas medium. We did not place any catalyst material into the reaction volume on purpose, but we used a mullite wool as one of the heat screen parts, and we believe, that the mullite wool was a source of Mg, Si, Ca, and Al found in catalyst particles of nanotubes. CNx nanotubes were characterized by transmission electron microscope JEM-2010 equipped with the EDS (Energy Dispersive X-Ray Spectroscopy) system. The TEM images have shown that the material consists of many Y-junctions with the main CNT stem and CNT branches. In most cases the angles between the branches are close to 120°. The nanotubes are 80–170 nm in diameter and have either one or several Y-junctions. Y-junction nanotubes both with short and long branches were observed. It is interesting that the short branches as well as those grown at the end of the process have a conic shape. Usually nanotubes are divided into identical compartments, but some of the observed nanotubes have the compartments of larger length. It is seen that all the Y-junction bamboo-like CNx nanotubes contain pear-shaped catalytic particles at the end. It is believed that the growth of branching structures occurs mainly due to the change of both physical and chemical properties of catalyst particles caused by different reasons. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|