Carbon Nanotubes and Nanofibers

A wide range of nanosfructured carbons has been discovered since fhe original discovery of carbon nanotubes (CNTs) by lijima in 1991. Carbon nanotubes and nanofibers are nanoscale cylinders of rolled up graphene sheets. 

Although the majority of authors who have investigated CNTs as supports for Pt and PtRu particles claim higher activity or performance compared to conventional catalysts, it is not clear why these enhancement arise. It seems unlikely that the CNTs provide any electronic enhancement to Pt(Ru) reactivity, so it is likely that CNTs provide benefits for catalyst layer structure. Part of this may be related to surface area because CNTs can have relatively high surface areas and are often compared to XC72 supported catalysts that have only a moderate surface area ( 250 m g ). Given the current high expense of these materials ( 10 kgr ), further benefits of their use need to be identified before fhey can be practically considered as candidates for fuel cell catalyst supports. 

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Serp, P, Corrias, M., and Kalck, P. 2003. Carbon nanotubes and nanofibers in catalysis. Applied Catalysis A General 253 337-358. 

Lee, K., Zhang, J., Wang, H., and Wilkinson, D. P. Progress in the synthesis of carbon nanotube- and nanofiber-supported Pt electrocatalysts for PEM fuel cell catalysis. Journal of Applied Electrochemistry 2006 36 507-522. 

Application of transmission electron microscopy (TEM) techniques on heterogeneous catalysis covers a wide range of solid catalysts, including supported metal particles, transition metal oxides, zeolites and carbon nanotubes and nanofibers etc. 

High-Pressure Hydrogenated Single-Walled Carbon Nanotubes and Nanofibers... 

Che, G., Lakshmi, B.B., Martin, C.R., and Fisher, E.R. Chemical vapor deposition based synthesis of carbon nanotubes and nanofibers using a template method. Chem. Mater. 10, 1998 260-267. 

A.N. Redkin, L.V. Malyarevich, Preparation carbon nanotubes and nanofibers by method of ultraspeed heating ethanol vapors. Inorganic.material, 2003, T. 39. JVb 4. pp. 433-437. 

For large scale production of carbon nanotubes and nanofibers chemical vapor deposition (CVD) method is most effective. Acetylene, ethylene, propylene, methane, natural gas (consisting predominantly of propane), carbon monoxide were used as a source of carbon [ 1 -8] (in view of large number of publications on CNT synthesis these references are selected arbitrary). Ethylene and possibly propylene are most convenient carbon sources for mass synthesis of high quality multiwall CNT (MWNT). 

Besides the traditional markets for carbon, some novel applications for the carbon produced via methane decomposition are discussed in the literature. Kvaemer has initiated R D program to investigate the potential of novel grades of carbon black as a storage medium for hydrogen, and as a feedstock for the production of solar grade silicone.35 The production of carbon nanotubes and nanofibers via solar thermal decomposition of methane over supported Co and Ni catalysts, respectively, was also reported.36... 

Rakov, E.G. (2004) Pyrolytic synthesis of carbon nanotubes and nanofibers, Ros. Khim. J. XLY111(5), 12-19. 

Carbon nanotubes and nanofibers have lately attracted great attention in nanomedicine including their potential use as drug carriers, although there are also considerable concerns associated with their safety (Lange et al., 2003 Muller et al.,... 

Che G, Lakshmi B, Maifin C, Fisher E, Ruoff R (1998) Chemical vapor deposition based syntliesis of carbon nanotubes and nanofibers usmg a template metliod. Chem Mater 10 260—267. 

At the beginning of the 2U century, it is thought that the improvement of the existing chemical industry will pass through the development of new kinds of catalysts to meet the latest environmental requirements. Since their discovery in 1991 [1], carbon nanotubes and nanofibers have received increasing interest in academic research and for several potential applications [2-4]. It has been reported by different authors that carbon nanofibers could be efficiently used as catalyst support for several catalytic reactions either in gas or in liquid phase [5-7], In both cases, the carbon nanofiber based catalysts always exhibited higher catalytic performances compared to those observed on equivalent conventional catalysts. 

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