Influence of chamber volume in single-walled carbon nanotube synthesis by an electric arc

V. Ramarozatovo (1) , A. Mansour (2) , Manitra Razafinimanana (3) , Marc Monthioux (4) , Flavien Valensi (3) , Laure Noé (4) , Mathieu Masquère (3)

1 Université d'Antananarivo
2 LAPLACE - LAboratoire PLasma et Conversion d'Energie
3 LAPLACE-AEPPT - Arc Electrique et Procédés Plasmas Thermiques
4 CEMES - Centre d'élaboration de matériaux et d'études structurales

Single-walled carbon nanotubes (SWCNTs) were produced by an electric arc process in a low-pressure chamber with vertical electrodes using heterogeneous graphite anodes containing nickel and yttrium catalysts. The influence of the chamber volume (18, 25 and 60L) and graphite grain size (1 and 100m) of the anode on the resulting products was analysed. This was correlated with the physical properties of the plasma as studied by optical emission spectroscopy and with the temperature of the gaseous atmosphere surrounding the plasma as measured using thermocouples. Nanotube yield and purity were evaluated from high-resolution transmission electron microscopy. Results showed a strong influence of the heterogeneous anode grain size. It was found that the optimal synthesis conditions correspond to an arc chamber volume of 25L and a graphite grain size of 1m. In that case the plasma temperature and the carbon over nickel concentration ratio in the plasma differ notably from those observed under the other synthesis conditions. It was also found that a slower temperature rise of the gaseous atmosphere surrounding the plasma and a higher anode erosion rate are associated with a higher SWCNT yield. These results were interpreted considering the vapour-liquid-solid nanotube formation model.

Mots clés: Synthesis conditions; Temperature rise; Vertical electrodes; Electric arcs; Emission spectroscopy; Grain size and shape; Graphite; Graphite electrodes; Nanotubes; Plasmas; Single-walled carbon nanotubes (SWCN); Thermocouples; Transmission electron microscopy; Yttrium; Atmospheric temperature; Anode erosion; Arc chamber; Gaseous atmosphere; Grain size; Graphite anode; Graphite grains; Nanotube formation; Nickel concentrations; Optimal synthesis; Plasma temperature; Single-walled carbon

Domaines: Physique [physics]

V. Ramarozatovo, A. Mansour, Manitra Razafinimanana, Marc Monthioux, Flavien Valensi, et al.. Influence of chamber volume in single-walled carbon nanotube synthesis by an electric arc. Journal of Physics D: Applied Physics, 2012, 45 (34), ⟨10.1088/0022-3727/45/34/345204⟩. ⟨hal-01760581⟩