Graphite nanofibers platelets

Pt (5 wt%) supported on platelet and ribbon graphite nanofibers exhibited similar activities to those observed by Pt (25 wt°/o) on carbon black [138], This phenomenon was attributed to the crystallographic orientations adopted by the catalyst particles dispersed on graphitic nanofiber structures [139]. Also, the electrocatalysts supported on CNFs were less susceptible to CO poisoning than Pt supported on carbon black. 

Graphitic nanofibers consist of graphite platelets stacked together in various orientations to the fiber axis with an interlayer distance similar to that of graphite. Depending on the orientation angle three distinct structures can exist tubular, platelet and herringbone (Fig. 6.9). 

Ambrosi, A., Sasaki, T., and Pumera, M. (2010) Platelet graphite nanofibers for electrochemical sensing and biosensing the influence of graphene sheet orientation. Chem. Asian J., 5, 266-271. 

Figure 3.2 Various graphite stacking arrangements in carbon nanofibers (a) platelets of graphite stacked perpendicular to the CNF axis, (b) angled stacking, and (c) stacking nearly parallel to the CNF axis. Reprinted with permission from [15].

Table 1 summarizes a survey of the synthetic approaches and resulting capacitance values of graphene-based electrodes (see also Refs. [5-7, 11, 14, 31, 76-80] for a review of synthetic approaches). Natural graphite is the most commonly used starting material, while more atypical materials such as CNTs [46] and platelet carbon nanofibers [55] have also been used. The (modified) Hummers method [81] is the most mutual method for oxidation of carbon, while the Staudenmaier [82] and Brodie [83] methods have also been applied. Reduction of the oxidized graphite oxide nanosheets is often conducted with hydrazine. 

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