Production of carbon nanotubes by the catalysed vapour phase pyrolysing process (II)

Al. Darabont1, N. Daróczi2, P. Nemes–Incze1, Zs. Sárközi1, Zs. E. Horváth3, K. Kertész3, A. A. Koós3, L. Tapasztó3, Z. Vértesy3, L. P. Biró3

1 Babeş–Bolyai University, Fac. of Physics, 400084 M. Kogălniceanu str., nr. 1, Cluj–Napoca, Romania
2 Babeş–Bolyai University, Fac. of Chemistry, 400028 Arany János str., nr. 11, Cluj–Napoca, Romania
3 MTA–MFA, Po Box 49, H–1525, Budapest

	High purity multi–walled carbon nanotubes (MWCNT’s) were synthesized by the catalytic decomposition of a solution of ferrocene in xylene. The solution was introduced in a quartz tube reactor, using the spray pyrolysis method. This type of CVD method and the experimental setup were described in detail in our previous papers [1], [2].
	The current paper focuses on our experimental findings, concerning the influence of the reactor temperature and the solution flow–rate on the quality and quantity of the MWCNT’s obtained. The influence of other important parameters, such as: carrier gas flow–rate and ferrocene content were investigated in our previous work [3]. The final product was purified by heating it in dilute nitric acid for several hours, than in distilled water. The quality of obtained carbon nanotubes was investigated by TEM.
	The spray pyrolysis method used by our group for the synthesis of MWCNT’s which operates at moderate temperatures, could be scaled up for continuous, or semi–continuous production of MWCNT’s.

[1]	L. P. Biró, Z. E. Horváth, A. A. Koós, Z. Osváth, Z. Vértesy, Al. Darabont, K. Kertész, C. Neamtu, Zs. Sárközi, L. Tapasztó, Direct synthesis of multi–walled and single–walled carbon nanotubes by spray pyrolysis Journal of optoelectronics and advanced materials – 3, 5., 661–666, 2003
[2]	Al. Darabont, K. Kertész, C. Neamţu, Zs. Sárközi, L. Tapasztó,L.P. Biró, Z.E. Horváth, A.A. Koós, Z. Osváth, Z. Vértesy, Production of carbon nanotubes by the catalysed vapour phase pyrolysing process Studia Universitatis Babes–Bolyai, Physica, Special Issue 2003
[3]	Al. Darabont, N. Daróczi, P. Nemes–Incze, K. Kertész, Zs. Sárközi, A. A. Koós, Zs.E. Horváth, Z. Osváth, Z. Vértesy, L. P. Biró, Synthesis of carbon nanotubes from liquid phase hydrocarbons in presence of catalysts Műszaki Szemle special edition 2005 (in press)