Carbon nanotubes cyclic voltammetry using

Figure 3.13 (a) Values of charge-transfer resistance of different systems based on carbon, using the redox probe Fe(CN)63 /4. (b) Nyquist plot of different carbon nanotube composites in the presence of the redox couple, (c) Table with the electron-transfer rate constants calculated from cyclic voltammetry data by using Nicholson method. Adapted with permission from Ref. [103], Copyright, 2008, Elsevier. 

PPy has also been used in combination with CNTs to obtain an anticorrosion coating. Hermas [69] studied PPy-CNTs coating applied on stainless steel by in situ EP of PPy-oxidised multi-walled carbon nanotubes (MWCNTs) and PPy-oxidised SWCNTs composites from 0.1 M oxalic acid by using cyclic voltammetry. The results show that the addition of the oxidised carbon nanotubes greatly enhances the EP process, especially in the case of oxidised SWCNTs. Similar results are reported in Ref. [70], referring to electrodeposition of a nanocomposite coating made of oxidised CNTs and poly(o-phenylenediamine) (PoPD) on a stainless steel. Also in this case the presence of the CNTs enhances the deposition of the PoPD and this enhancement is more evident with SWCNT than with MWCNTs. The nanocomposite coating keeps the stainless steel in a passive state in an acidic solution. 

Cyclic voltammetry (CV) was used in order to investigate the electrocatalytic ORR performance, and results suggested good electrocatalytic activity of these TiN nanocrystals for oxygen reduction. Electrocatalytic studies also showed that the TiN NTs have better catalytic performance than TiN NPs. The results demonstrate that the structure of the nanotubes plays an important role in the ORR activity, which the authors attribute to favorable electron conduction and electrolyte diffusion. It was noted however that although the activities are comparable, the ORR activity of carbon-coated TiN NTs (the best performing material) was lower than that of Pt/C. 

Recently, a cholesterol biosensor was developed using cholesterol oxidase function-ahzed on multiwall carbon nanotubes film—modified glassy carbon electrode (ChOx/ MWCNTs/GCE) (Li et al., 2011 Figure 3.7). The electrocatalytic behavior toward cholesterol was investigated by cyclic voltammetry. This sensor showed excellent perfor-... 

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