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Carbon nanotubes from ethanol on Fe-Co/MgO catalysts and related interface phenomena

D. LUPU1, A. R. BIRIŞ1, I. BALTOG2, M. BAIBARAC2, V. KUNCSER2, G. SCHINTEIE2, M. VALEANU2, S. LEFRANT3, A. S. BIRIS4, I. MIŞAN1, G. FILOTI2,*

Affiliation

  1. National Institute for R&D of Isotopic and Molecular Technologies, Cluj-Napoca, Romania
  2. National Institute for R&D of Materials Physics, Bucharest, Romania
  3. Institut des Matériaux Jean Rouxel, Laboratoire de Physique Cristalline, Nantes, France
  4. Applied Science Department, University of Arkansas at Little Rock, AR, USA

Abstract

Mössbauer spectroscopy studies of Fe-Co/MgO catalysts proved that a high dispersion degree of Fe may be achieved for catalysts containing Fe/Co in a ratio close to 1. During materials processing. the presence of hydrogen at high temperatures, even for short time, induced an increased particle size of the catalytic Fe. The evaluation of various iron species from their areas in the Mössbauer spectra revealed the dependence of the nanotube amount on (FeCo alloy + Fe2+) content in the catalyst, in good agreement with literature mechanisms. The Raman spectra show that carbon nanotubes synthesized from ethanol in argon flow on 4.5%Fe:4.5%Co/MgO are richer in low diameter (0.7-1.0nm) tubes than those obtained at low ethanol pressure, in agreement with the effects of hydrogen reported in literature. The close similarity with the Raman spectra of Aldrich double-walled carbon nanotubes and from literature, recommends the syntheses in argon flow as better conditions for double-walled carbon nanotube growth..

Keywords

Carbon nanotubes, Fe-Co/MgO catalyst, Mossbauer spectroscopy.

Submitted at: Jan. 15, 2009
Accepted at: March 24, 2009

Citation

D. LUPU, A. R. BIRIŞ, I. BALTOG, M. BAIBARAC, V. KUNCSER, G. SCHINTEIE, M. VALEANU, S. LEFRANT, A. S. BIRIS, I. MIŞAN, G. FILOTI, Carbon nanotubes from ethanol on Fe-Co/MgO catalysts and related interface phenomena, Journal of Optoelectronics and Advanced Materials Vol. 11, Iss. 3, pp. 338-347 (2009)