Carbon nanocoil

Helical (carbon) nanocoils have received attention recently255-257 for their properties as field emitter and thus for the fabrication of flat panel field emission displays. The properties depend on the electrical field generated due to the helical nanostructure, and to the characteristics of the tip of the carbon nanocoil. In fact, carbon... 

Barranco, V., V. Celorrio, M. J. Lazaro, and J. M. Rojo. 2012. Carbon nanocoils as unusual electrode materials for supercapacitors. Journal of the Electrochemical Society... 

Rakhi et al reported the conducting-polymers (polyaniline [PANI] and PPy)-coated carbon nanocoils (CNCs) as efficient binder-free electrode materials for supercapacitors for the first time, in which the CNCs acted as a perfect backbone for the uniform distribution of the conducting polymers in the composites [16]. Ihe SC and maximum storage energy per unit mass of the composites were found to be comparable to one of the best-reported values for polymer-coated MWNTs. Dumanli et al. prepared the chemically bonded carbon nanofibers (CNFs)-PPy composite via electro-polymerization of Py on CNFs [17]. It showed that the final capacitance values were highly dependent on the number of deposition cycles and deposition rates. The best result for the coiled CNF-PPy composite system was found to be 27.6 C/cm at six times cycling using 25 mV/s. 

Hyeon T, Han S, Sung Y-E, Park K-W, Kim Y-W. High-performance direct methanol fuel cell electrodes using solid phase synthesized carbon nanocoils. Angew Chem hit Ed 2003 42 4352-6. 

Hyeon et al. [116] successfully synthesized carbon nanoeoils composed of nanometer-thiek graphitic fibers by the catalytic graphitization of a resorcinol-formaldehyde gel. The carbon nanocoils were applied as eleetrode materials for direct methanol fuel cells. The SEM image reveals that the carbon materials consisted of partieles approximately 100 mn in diameter (Figure 10.14(a)). The TEM image (Figure 10.14(b)) shows that each individual particle is composed of... 

We conclude that carbon nanocoils (CNCs) are an excellent support for flie electrodes of direct methanol fuel cells. Further, the CNC maintains stable catalytic activity by measuring power density versus time for up to 100 hr in a DMFC unit cell in the performance of fuel cells since the durability of the electrode is significant for long-term applications, it is believed that the CNC is a highly promising electrode for long-term fuel cells. However, since the issue of durability and stability of the fuel cell electrode is very important, more in-depth study of these characteristics is still underway. 

The production of nanostructured carbon materials by hydrothermal processes from natural precursors is one of the most attractive subjects in material science today. Carbon materials prepared from hydrothermal process are currently being used in various fields of research including environmental, electrical, chemical, and biomedical fields. In environmental application, carbon is mainly used as a sorbent material for the removal of heavy metal ions (CrO/, Pb +, and Cd +) from water and wastewater [116,117]. Carbon nanocoils prepared from saccharides (sucrose, glucose, and starch) with a support of Pt/Ru nanoparticles exhibit a high catalytic activity for the electro-oxidation of methanol in an acid medium [150]. Similarly, electro-oxidation of ethanol and methanol was carried out with electro catalysts, such as Pd/CHC (coin-like hollow carbon), Pt/ HCS (hard carbon spherules), and Pt/Pd/CMS (carbon microspheres) in acidic and alkaline media... 

M. Sevilla, G. Lota, and A. B. Fuertes, Saccharide-based graphitic carbon nanocoils as supports for Pt/ Ru nanoparticles for methanol electrooxidation. J. Power Sources, 171,546-511, 2007. 

Carbon nanocoils, as well as carbon nanotubes, constitute a new class of carbon nanomaterials with properties that differ significantly from other forms of carbon. The structure of a nanocoil is similar to that of MWCNTs, except helical shape. The catalysts supported on carbon nanocoils exhibited better electrocatalytic performance compared with the catalyst supported on Vulcan XC-72 carbon. In particular, the Pt-Ru alloy catalyst supported on the CNC, which has both good crystallinity and a large surface area, showed a superior electrocatalytic performance, compared with other CNC catalysts [43]. A fuller-ene (Cso) film electrode was also suggested as a catalyst support for methanol oxidation after electrodeposition of Pt on these fullerene nanoclusters [44]. 

Park, K.-W., Sung, Y.-E., Han, S., Yun, Y., and Hyeon, T. (2004) Origin of the enhanced catalytic activity of carbon nanocoil-supported PtRu alloy electrocatalysts. Journal of Physical Chemistry B, 108 (3), 939-944. 

Similarly, Ueda and colleagues utilized carbon nanofibers as templates, although this required multiple coating with a solution of an alkoxide precursor in organic solvents to achieve stable zirconia structures after calcination. On the other hand, by using carbon nanocoil templates, even coiled structures could be prepared, as shown in Figure 8.10 [118]. 

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