Selective Synthesis and Characterization of Single Walled Carbon Nanotubes (11, 8)

Abstract

Single walled carbon nanotubes (SWCNTs) are attractive in the nanotechnology industry where they find applications in the field of pharmacy and medicine due to high surface area capable of transporting drugs and vaccines to active sites; for fabrication of energy storing devices due to excellent electrical conductivity and accessible pore sizes; in transport for the fabrication of strong and lightweight vehicle and aircraft parts and in composite materials to enhance physical and chemical properties such as toughness, durability, conductivity and strength. The most efficient and cost effective method of obtaining these precious materials is the Chemical Vapour Deposition (CVD), however, obtaining SWCNTs of desired electronic type via this method, has remained a global challenge for over 20 years. This has limited the availability of these products in the global research and technological industries, contributing to the problem of lack of raw materials to sustain them. In this report, metallic SWCNTs (11, 8) are selectively synthesized via chemical vapor deposition (CVD) method, by the pyrolysis of C 6 H 14 /N 2 feedstock on Fe 2 O 3 /Al 2 O 3 catalyst matrix. Catalyst design and preparation was achieved by correlating the numerical magnitudes of chiral index (n, m) of the desired SWCNTs with mole fractions of metal/support, respectively. Field emission scanning electron microscopy analysis reveals densely entangled tubular bundles, while high resolution transmission electron microscopy confirms rigid arrangements of SWCNTs in the bundles. Values of the radial breathing modes, diameter and energy band gaps of the sample obtained from Raman analysis conforms to that of SWCNTs (11, 8), established via Extended Tight Binding (ETB) model. Outcome of this report suggested that our catalyst design and preparation may help alleviate the stated global challenge.