Alkali-doped carbon nanotubes

Chen, P., X. Wu, J. Lin, K.L. Tan, High H2 uptake by alkali-doped carbon nanotubes under ambient pressure and moderate temperatures. Science (Washington, DC) 285(5424), 91-93,... 

Yang, R.T., Hydrogen storage by alkali-doped carbon nanotubes. Carbon 38(4), 623-626, 2000. 

A schematic cell is shown in Figure 23.8. Since the KOH electrolyte absorbs CO2, it is necessary to use a pure H2 source, so a reformate cannot be used. On-board H2 storage causes no emissions and alkali doped carbon nanotubes have a high storage capacity. 

Chen P., Wn X., Lin J., and Tan K.L. (1999) High H-2 uptake by alkali-doped carbon nanotubes under ambient pressnre and moderate temperatures . Science, 285, 91-93. 

Froudakis, G.E. (2001). Why alkali-metal-doped carbon nanotubes possess high hydrogen uptake. Nano Lett., 1, 531-3. 

No superconductivity has yet been found in carbon nanotubes or nanotube arrays. Despite the prediction that ID electronic systems cannot support supercon-ductivity[33,34], it is not clear that such theories are applicable to carbon nanotubes, which are tubular with a hollow core and have several unit cells around the circumference. Doping of nanotube bundles by the insertion of alkali metal dopants between the tubules could lead to superconductivity. The doping of individual tubules may provide another possible approach to superconductivity for carbon nanotube systems. 

The filling control approach has even been applied to some nanophase materials. For example, the onset of metallicity has been observed in individual alkali metal-doped single-walled zigzag carbon nanotubes. Zigzag nanotubes are semiconductors with a band gap around 0.6 eV. Using tubes that are (presumably) open on each end, it has been observed that upon vapor phase intercalation of potassium into the interior of the nanotube, electrons are donated to the empty conduction band, thereby raising the Fermi level and inducing metallic behavior (Bockrath, 1999). 

The best performance for non-commercial AEM corresponds to active DMFC with copolymers of vinylbenzyl chloride and metacrylates [220] and alkali-doped PBI [223]. Regarding the performance of commercial AEM in DMFC assays, the results are quite modest in terms of MPD, except for the A-006 membrane from Tokuyama. Prakash et al. [248] reported MPD up to 170 mW.cm at 90 °C in active cells using a high load (8 mg.cm ) Pt -Ru anode, while Bianchini and coworkers [250,251 ] have obtained MPD between 95 and 120 mW.cm at 80 °C in active cells using Pd supported on multiwall carbon nanotubes and on Ni-Zn/C as anodic catalyst. 

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