Environmental Engineering Reference
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FIGURE 7.4 Representative TEM images of parent carbon materials: (a) amorphous carbon, (b) ribbon
CNFs, (c) platelet CNFs and (d) fishbone CNFs. Source : Reproduced with permission from Jimenez
et al. [25].
surface area. It is potentially useful for hydrogen storage due to its low cost
and accessibility on a commercial scale [27]. For hydrogen storage, the rate
and capacity of the activated carbon are influenced by its morphology and
shape, that is, powder, fiber, and granular. For conventional AC, the hydrogen
update is proportional to its surface area and pore volume, and high adsorp-
tion capacity is only achieved at very low cryogenic temperature and high
pressure. Various types of commercial and modified AC have been exten-
sively studied. For example, the capacity of hydrogen storage has been
studied for electrospun-activated carbon fibers prepared by electrospinning
and chemical activation based on the comparison with other carbon materials
such as active carbon, single-walled carbon nanotube, and graphite [28]. The
hydrogen adsorption capacity of chemically activated electrospun carbon
fiber is better than that of other porous carbon materials, which is attributed
to the optimized pore structure of electrospun-activated carbon fibers that
might provide better sites for hydrogen adsorption than other carbon materi-
als. Figure 7.5 shows some representative SEM images of several electrospun-
activated carbon fibers, which all exhibit highly uniform diameters.
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