Few-walled carbon nanotubes

Isogai S, Ohnishi R, Katayama M, Kubota J, Kim DY, Noda S, Cha D, Takanabe K, Domen K (2012) Composite of TIN nanoparticles and few-walled carbon nanotubes and its application to the electrocatalytic oxygen reduction reaction. Chem Asian J 7 286-289... 

Qian C, Qi H. et al.. Fabrication of small diameter few-walled carbon nanotubes with enhanced field emission property. Journal of Nanoscience and Nanotechnology, 2006. 6(5) 1346-1349. 

Modification of native cellulose nanofibers by functionalized-few-walled carbon nanotubes for hybrid nanofiber/nano-tube aerogels [49]... 

Lee SW, Gallant BM, Lee Y et al (2012) Self-standing positive electrodes of oxidized few-walled carbon nanotubes for light-weight and high-power lithium batteries. Energy Environ Sci 5(l) 5437-5444... 

Because of the speeial atomie arrangement of the earbon atoms in a carbon nanotube, substitutional impurities are inhibited by the small size of the carbon atoms. Furthermore, the serew axis disloeation, the most eommon defeet found in bulk graphite, is inhibited by the monolayer strueture of the Cfj() nanotube. For these reasons, we expeet relatively few substitutional or struetural impurities in single-wall earbon nanotubes. Multi-wall carbon nanotubes frequently show bamboo-like defects associated with the termination of inner shells, and pentagon-heptagon (5 - 7) defects are also found frequently [7]. 

CNTs may consist of just one layer (i.e. single-walled carbon nanotubes, SWCNTs), two layers (DWCNTs) or many layers (MWCNTs) and per definition exhibit diameters in the range of 0.7 < d < 2 nm, 1 < d < 3 nm, and 1. 4 < d < 150 nm, respectively. The length of CNTs depends on the synthesis technique used (Section 1.1.4) and can vary from a few microns to a current world record of a few cm [16]. This amounts to aspect ratios (i.e. length/diameter) of up to 107, which are considerably larger than those of high-performance polyethylene (PE, Dyneema). The aspect ratio is a crucial parameter, since it affects, for example, the electrical and mechanical properties of CNT-containing nanocomposites. 

A single-walled carbon nanotube (S WNT) is a single graphene sheet rolled up in a seamless cylinder, whose diameter is of the order of few nanometers (Fig. 4.12). A double-walled carbon nanotube (DWNT) consists of rolled two graphene layers, and a multiwall carbon nanotube (MWNT) exhibits several co-axial rolls of graphene sheets, one sitting in each other and separated by about 0.35 nm. 

Ni(CO)4 is the sole binary carbonyl complex of the elements of group 10 that is stable (Table 8.1). However, very few studies in which Ni(CO)4 is used in the preparation of catalysts have been reported [43]. This is probably due to the difficulty of manipulation of Ni(CO)4 and its very high toxicity. However, surface Ni(CO)4 species have been identified after the interaction of CO with highly dispersed supported nickel catalysts prepared by other routes [44]. Recent interest in the use of Ni(CO)4 has focused on the controlled production of nickel nanoparticles for specific purposes, such as in automotive converters [45]. The use of nickel tetracarbonyl as an agent for the nucleation process in the growth of single-wall carbon nanotubes has also been reported [46]. 

Five years after the discovery of fullerenes, Iijima reported in 19911 a novel form of organized carbon which consists of hollow cylindrical structures, a few nanometers in diameter and some micrometers long. Although hollow carbon nanofibers had been prepared for several decades, their walls had never been resolved by High-Resolution Transmission Electron Microscopy (HRTEM). These HRTEM images allowed Iijima to conclude that the walls of the so-called multi-walled carbon nanotubes (MWCNTs) are made up of several concentric cylinders, each being formed by a graphene sheet rolled... 

In general, functionalization reactions of SWNTs are very slow and take several days to proceed. In this respect, microwave irradiation seems to be a potentially powerful tool to functionalize SWNTs but only a few such reactions have been described to date. One example of the application of microwaves was described by Della Negra et al. [88]. Soluble single-walled carbon nanotubes were synthesized by grafting poly(ethylene glycol) (PEG) chains on to SWNTs. Use of microwave irradiation enhanced reaction rates in comparison with similar syntheses using conventional heating. An amidation reaction has also been performed, in two steps, under microwave irradiation conditions (Scheme 21.23) [89]. Amide-SWNT derivative 68 was synthesized by reaction of 2,6-dinitroaniline and the carboxylic acid-... 

Carbon nanotubes (CNT) consist of molecular cylinders of pure, hexag-onally-arranged carbon atoms with a diameter of a few nanometres and a length of many microns. They occur in two main forms the single-wall carbon nanotube (SWNT) composed of a single lattice cylinder of carbon, and the multi-wall nanotube (MWNT) version, consisting of concentric lattice cylinders of carbon they resemble one cylinder within another. The ends of the tubes are usually closed off by a carbon end-cap, also in lattice form. 

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