Science and Technology Production
SYNTHESIS OF CARBON NANOTUBES BY CVD: EFFECT OF ACETYLENE PRESSURE ON NANOTUBES CHARACTERISTICS
Article
Authorship:
Mariano Escobar ; Sergio Moreno ; Roberto J. Candal ; MARCHI, MARIA CLAUDIA ; Alvaro Caso ; Pablo Polosecki ; Gerardo H. Rubiolo ; Silvia GoyanesDate:
2007Publishing House and Editing Place:
ELSEVIER SCIENCE BVMagazine:
APPLIED SURFACE SCIENCE, vol. 254 (pp. 251-256) ELSEVIER SCIENCE BVSummary *
The effect of acetylene partial pressure on the structural and morphological properties of multi-walled carbon nanotubes (MWCNTs) synthesized by CVD on iron nanoparticles dispersed in a SiO2 matrix as catalyst was investigated. The general growing conditions were: 110 cm3/min flow rate, 690 °C synthesis temperature, 180 Torr over pressure and two gas compositions: 2.5% and 10% C2H2/N2. The catalyst and nanotubes were characterized by HR-TEM, SEM and DRX. TGA and DTAwere also carried out to study degradation stages of synthesized CNTs. MWCNTs synthesized with low acetylene concentration are more regular and with a lower amount of amorphous carbon than those synthesized with a high concentration. During the synthesis of CNTs, amorphous carbon nanoparticles nucleate on the external wall of the nanotubes. At high acetylene concentration carbon nanoparticles grow, covering all CNTs’ surface, forming a compact coating. The combination of CNTs with this coating of amorphous carbon nanoparticles lead to a material with high decomposition temperature. Information provided by the agent in SIGEVAKey Words
Carbon nanotubesX-ray diffractionIron catalystsAcetylene decompositionThermal analysisChemical vapor depositionScanning and transmission electron microscopy