Materials nanotubular

The similarity of M0S2 to graphite has been noted. Like elemental carbon, which has been found to form nanotubular stmctures, M0S2 has also been found to form nested stmctures upon exposure to the electron beam in an electron microscope (23). Moreover, M0S2 displays a variety of intercalation reactions typical of layered materials. Single-layer M0S2 has been successfully prepared and manipulated (22). 

Frackowiak E., Jurewicz K., Delpeux S., Beguin F. Nanotubular materials for supercapacitors. J Power Sourc 2001 97-98 822-5. 

Structural aspects of these nanoparticles are also discussed in this chapter. Extensive mathematical research has been devoted to polyhedramade of a single layer (13). Surprisingly, however, mathematical analysis of polyhedra and nanotubular structures made of two interconnected layers and more has started only very recently, as a result of the discovery of IF phases [see, e.g., (14)]. Most of the inorganic layered materials are comprised of more than one atomic layer, with strong chemical bonds interconnecting between the atoms of the different layers. Therefore a mathematical analysis of multilayer polyhedra is called for. 

A.L. Ivanovsky. Quantum chemistry in material science. Nanotubular forms of substance. Ekaterinburg, UrD RAS, 199,176 p. 

Finally, the other factor that could contribute to the improved performance of the nanotubule electrode is its higher surface area. This higher surface area would make the true current density at the nanotubular material lower than at the control material. In order to access the contribution of surface area, Brunauer-Emmett-Teller (BET) measurements were made on both the nanotubular and control electrodes [124], The specific surface areas were found to be 40 m g (nanotubule electrode) and 13 m g (control electrode). This factor of 3 increase in surface area cannot account for the factor of 12 improvement in capacity observed at the highest current... 

Similar issues were raised by Beguin et al. [97] regarding the capacitance properties of carbons in general and nanotubes in particular, because the higher the... oxygen content of the nanotubes, the higher the capacitance value, whereas after a few cycles, the capacitance of nanotubular materials rich in surface groups noticeably decreases the authors did not discuss the reasons for such behavior. 

Nanotubes of MoS2, WS2 and a few other layered materials are single-crystalline in the sense that the layers run through the entire structure. Some of the chalcogenide nanotubes are, however, polycrystalline, the nanotubular form being produced by an aggregation of nanoparticles, just as in some of the metal oxide nanotubes. 

Many metal oxides have been made in the form of nanotubes, but most of them have an amorphous wall. SEM is normally used to characterize these materials. For some crystalline oxide nanotubes, HRTEM is the only technique to determine their structures. Titania-related nanotubular material is a good example. 

Most of the reported nanostmctured actinide compounds considered here have been obtained under soft S5mthesis conditions (room-temperature crystallization from aqueous solutions). Most of these compounds are soluble and it is rather hard to foresee any practical application of them. However, findings reported here demonstrate the possibility of nanoscale fabrication for actinides in higher oxidation states. For instance, we expect that a whole new range of uranium-based nanotubular and nanocomposite materials can be... 

Frackowiak, E., Jurewicz, K., Szostak, K., Delpeux, S., and Beguin, F. (2002). Nanotubular materials as electrodes for supercapacitors. Fuel Process. Tech., 77—78, 213-9. 

Values of capacitance (F g ) for different nanotubular materials in 6 mol L KOH [74], Reprinted with permission from E. Frackowiak, K. Jurewicz, S. Deli ux and F. Beguin, J. Power Soutc., 97-98 C2001) 822... 

Therefore, it has been proposed to use a mmlerate amount of nanotubular materials as surface area enhancing component and electronic conductor in ECP-based electrodes [14,74,93-98]. Carbon natmtubes (CNTs), due to their unique morphology and extended grrphitic layers (see Fig. 16), are characterized by exceptional conducting and mechanical... 

Cycle stability and stability of the structural integrity of the nanostructured material are further important requirements of electrochromic materials. The CV curves presented in Fig. 6. lOd, e indicate that the nanotubular NiO structures exhibits good long-term cycle stability, giving rise to a pair of well pronounced redox peaks. Fur-... 

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