Low-Energy, Catalyst-Free Synthesis of Carbon Nanotubes
V. Krishna, B. Koopman, B. Moudgil
University of Florida, US
Keywords: MWNT, Laser, functionalized fullerenes
Abstract:Carbon nanotubes (CNTs) can be synthesized by various techniques such as arc-discharge, laser ablation, chemical vapor deposition (CVD) and templated synthesis. The first two techniques usually use graphite as the source of carbon while the latter two techniques use carbon monoxide or other hydrocarbons as the source. Formation of CNTs by laser ablation usually requires laser intensities in the range of 1–3 MW/cm2. CNTs have also been synthesized by thermal treatment of carbon nanostructures. Synthesis of single-wall and multi-wall carbon nanotubes (MWNTs) usually requires catalyst. We have discovered a new method of synthesizing CNTs without the need for catalyst, by molecular transformations of functionalized fullerenes. Low-intensity laser irradiation of functionalized fullerenes, such as polyhydroxy fullerenes, in oxygen-free environment results in transformation of fullerenes to various carbon nanostructures including MWNTs and carbon nanohorns. The MWNTs formed by this method have highly graphitized structure. The novel synthesis route has potential applications in fabricating homogenous polymer composites, hydrogen storage, electronics and therapeutics. We have filed a provisional patent (UF#12991) for this technology.