Study of the samples of carbon nanotubes synthesized on alumina supports with different contents of iron Roya Aghababazadeh 1,* , Alireza Mirhabibi 1, 2 and Hajar Ghanbari 1,2 , Rick M. Brydson 3 and Andrew P. Brown 3 1 Iran Colour Research Centre, Afshari st., Hemmat Highway Junction, Tehran, Iran. 2 Materials and Metallurgy Department, Iran University of Science and Technology, Tehran, Iran. 3 Institute for Materials Research, Leeds University, Leeds, UK Email: r_babazadeh@yahoo.com Keywords Carbon nanotubes, Chemical Vapour Deposition, Raman spectroscopy INTRODUCTIORN Carbon nanotubes (CNTs) exhibit many unique and useful physical and chemical properties (Popov, 2004). These materials were observed for the first time by Radushkevich and Lukyanovich in 1952 (Kuzentsov, 2003) but only after the discovery of Single-wall nanotubes (SWNTs) in arc discharge deposit by Iijima in 1991 (Iijima, 1991) its importance realized and convert to one of the significant subject of research in nanoscience. Monitoring and controlling the process by different methods were established by many researches all over the world (Ando, 2004). One of these methods that have the potential of being scaled up is CVD that was used for synthesis of different species of materials such as carbon filaments for many years (Baker, 1972). Optimizing the CVD parameters for CNTs formation with predetermined properties is one the goal of these investigations (Heffner, 1998). We used CCVD method to study CNTs synthesis over different alumina substrate which impregnated with different contents of iron as metal catalyst. EXPERIMENTAL The Fe/Al 2 O 3 catalysts were prepared by wet impregnation technique. We used Fe 2 (SO 4 ) 3 .5H 2 O (Aldrich, 97%) as iron precursor for impregnation the nanopowder of Alumina supports (γ-δ-θ from Deggusa) with iron particles. Appropriate amount of alumina was suspended in ethanol (Merck, >99%) and different amount of aqueous sulphate was added to the suspension to satisfy the ratios of Fe: Al2O3 mentioned in table 1. After stirring for 10 minutes, they were heated up to 70 C. Then the dried powder was ground in agate mortar and used for CNT synthesis. The synthesis of CNTs was carried out in a fixed bed reactor consisting of a horizontal furnace with a quartz tube. Typically, approximate 10 mg of as-prepared catalyst was uniformly dispersed in the base area of an alumina boat and placed in the central region of the tube. After the furnace was purged by N 2 with flow rate of 0.3 lit/min from ambient temperature to 900 C, CH 4 (99.999%) at a flow rate of 6 lit/min was introduced into the tube for 30 min and then again N 2 passed over the reacted catalysts until cooling the furnace to room temperature. The catalysts and as-grown products were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy and, X-ray diffraction (XRD). * Corresponding author. Tel.: +98-21-22535441; Fax: +98-21-