الفهرس 
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Abstract
High quality SWCNTs have been successfully synthesized by using
catalytic chemical vapor deposition of methane over various iron-based
catalysts. The Fe-containing catalysts used in this study were classified into
two main categories according to the promoter type and the preparation
method. The catalytic runs were conducted at 900 oC under atmospheric
pressure using horizontal fixed-bed flow reactor. The fresh catalysts were
characterized by XRD, N2 physisorption, TPR, whereas the morphology
and microstructure of as-grown SWCNTs were characterized by TEM,
TGA, and Raman spectroscopy.
In the first part, the effect of Mo or Cu doping on the catalytic growth
activity of Fe/MgO catalyst for synthesis of SWCNTs through methane
decomposition was studied. Accordingly, a series of mono-, bi- and
trimetallic Fe-based catalysts, i.e., 6%Fe, 5%Fe-1%Mo, 5%Fe-1%Cu or
4%Fe-1%Mo-1%Cu/MgO, respectively with equal metal contents were
prepared by impregnation method and tested. The obtained results showed
that all catalysts produced mainly SWCNTs with different yield and
quality. Among the catalysts tested in this series, the 5%Fe-1%Mo/MgO
catalyst was the most effective for growing SWCNTs. TEM and Raman
analyses illustrated that high yield with better quality of SWCNTs was
obtained over Fe-Mo or Fe-Mo-Cu/MgO catalysts compared to the
monometallic Fe/MgO catalyst at the same synthesis conditions.