Carbon nanotubes with high specific surface area

Carbon nanotubes, due to their unique properties, have numerous applications, especially when conjugated with biomacromolecules. As far as the immobilization of proteins concerns, the high specific surface area of these nanomaterials facilitates the immobilization of more protein molecules on the carrier material, which is accompanied by an increased specific enzyme activity. 

Fig. 32. Desorbed amount of hydrogen versus the BET specific surface area for carbon nanotubes and high sur ce area graphite samples [123], Reprinted with permission fiom A. ZUttel, P. Sudan, P. Mauran, T. Kioyob ashi, Cimmenegger, and L. Schlapbach, InL J. Hydrogen Enei , 27 (2002). 203.

As compared to SWCNTs, the properties of capacitors based on double-wall carbon nanotubes (DWCNTs) were not published so frequently, as pure DWCNTs are very hard to obtain. Basically, DWCNTs and multiwall carbon nanotubes (MWCNTs) have a lower surface area for EDL formation as compared to SWCNTs. On the other hand, a variety of works on capacitive performance of MWCNTs has been published, as they are relatively easily synthesized and are much cheaper than SWCNTs. As dependent on the methods of synthesis and modifications, different types of MWCNTs with different specific surface area values were obtained. Their specific capacitance values obtained in aqueous and nonaqueous electrolytes are from 10 to 100 F/g. However, they are not so high as in the case of ACs. On the other hand, one must point out that bulk capacitance is relatively high because of high bulk density of MWCNTs. Synthesis of MWCNTs is often carried out by pyrolysis of ethylene using catalysts, for example, Fe-Co. 

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