**1. Introduction**

Carbon nanofibers are linear filaments with diameter of 100 nm that are characterized by flexibility and their aspect ratio above 100. Materials as fiber are of extraordinary viable and scientific significance. The blend of high specific area, flexibility and high mechanical strength permit nanofibers to be utilized in our everyday life in addition creating arduous composites for vehicles and aviation. Be that as it may, they ought to be discriminated from conventional carbon fibers [1–3] in their small diameter (**Figure 1**). Conventional carbon fibers have a few micrometer-sized diameters.

Likewise, they are not quite the same as notable carbon nanotubes [5–9]. Carbon nanofibers could be developed by passing carbon feedstock nanosize estimated metal particles at high temperature [5, 10–15], which is fundamentally the same as the development state of carbon nanotubes.

Such a unique structure renders them to show semi-conducting behavior [16] and to have chemically active end planes on both the inner and outer surfaces of the nanofibers, thereby making them useful as supporting materials for catalysts [17], reinforcing fillers in polymeric composites [18], hybrid type filler in carbon fiber reinforced plastics [19–21], and photocurrent generators in photochemical cells [22, 23].

Though, their geometry is not quite the same as concentric carbon nanotubes containing a whole empty core, since they can be pictured as normally stacked shortened conical or planar layers along the filament length [24–27]. Such a one of a kind

**Figure 1.** *Schematic comparison of the diameter dimensions for various types of fibrous carbons [4].*

structure renders them to show semi- conducting behavior [16] and to have synthetically dynamic end planes on both the inner and outer surfaces of the nanofibers, in this way making them helpful as supporting materials for catalysts [17], reinforcing fillers in polymeric composites [18], hybrid type filler in carbon fiber reinforced plastics [19–21], and photocurrent generators in photochemical cells [22, 23].
