Perspectives of Single-Wall Carbon Nanotube Production in the Arc Discharge Process

Single-wall carbon nanotubes (SWNTs) promise wide applications in many technical fields. As a result purified SWNT material is sold now on the West market at more than $1000 per 1 gram. Thus developing an effective technology for SWNTs production rises to a very important scientific problem. The perspectives of three existing methods providing raw material in the technology of SWNT production have been analyzed. They are i) pulsed laser evaporation of graphite/metal composites, ii) evaporation of graphite electrodes with metal content in the arc discharge process, and iii) catalytic decomposition of the mixture of CO and metal carbonyl catalyst precursor. The observed dynamics of SWNT market points to replacing the laser method of SWNTs production by the arc process. The conclusion has been made that the technology based on the arc process will be the major one for the fabrication of purified SWNTs at least for the next five years. A reliable estimation of a low price limit of SWNTs was derived from a comparison of two technologies based on the arc discharge process: the first one is the production of SWNTs and the second one is the production of a fullerene mixture С60 + С70. The main conclusion was made that the price of purified SWNTs should always be more by 2-3 times the price of fullerene mixture. The parameters of a lab-scale technology for the production of purified SWNTs are listed. A large-scale application of the developed technology is expected to reduce the price of purified SWNTs by approximately ten times. The methods now employed for the characterization of products containing SWNTs are briefly observed. It is concluded that electron microscopy, thermogravimetric analysis, absorption and Raman spectroscopy, measurement of the specific surface aria, optical microscopy - each in separation is not enough for extensive characterization of a sample containing SWNTs, and all these methods should be used together

Role of non-covalent interactions at the oxidation of 2,5-di-Me-pyrazine-di-N-oxide at glassy carbon, single-walled and multi-walled carbon nanotube paper electrodes

Recently in our work it was shown that the catalytic efficiency of organic compound oxidation in the presence of electrochemically generated radical cations of aromatic di-N-oxides was increased several times using single-walled (SWCNT) or multi-walled (MWCNT) carbon nanotube paper electrodes instead of glassy carbon (GC) electrode. It was found that, in the absence of substrate, the oxidation currents of di-N-oxides at SWCNT or MWCNT paper electrodes, in contrast to the GC electrode, exceeded the oxidation current of the ferrocene (Fc) reference several times. In this work, the study of 2,5-di-Me-pyrazine-di-N-oxide (Pyr1) and Fc oxidation in 0.1 M Bu4NClO4 solutions in acetonitrile (MeCN) at GC, SWCNT and MWCNT paper electrodes was performed by methods of cyclic voltammetry, electron paramagnetic resonance (EPR) electrolysis, and differential capacitance. Quantum chemical modeling of adsorption of Pyr1, Fc, and MeСN on CNT surface was carried out using a cluster model describing the surface of conducting and non-conducting carbon nanotubes. The adsorption energies, equilibrium distances for molecular location and orientation on CNT surface were obtained. The observed effects were explained on the basis of quantum chemical modeling of the non-covalent interaction of the components of the studied system with CNT surface