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The metal is capable of forming nanosize carbon structures, and growing nanosize carbon structures by means of a chemical vapor deposition method on the treated carrier in a gas atmosphere comprising a carbon-containing gas, followed by an optional surface modification step. This process allows optimizing porosity, hydrodynamical properties and ...
Schematic of a lithium-air battery. For the nanofiber-based lithium-air battery, the cathode would be made up of carbon nanofibers. The performance of these batteries depends on the characteristics of the material that makes up the cathode. Carbon materials have been widely used as cathodes because of their excellent electrical conductivities ...
Filamentous carbon is a carbon-containing deposit structure that refers to several allotropes of carbon, including carbon nanotubes, carbon nanofibers, and microcoils. [1] [2] [3] It forms from gaseous carbon compounds. [1] Filamentous carbon structures all contain metal particles. These are either iron, cobalt, or nickel or their alloys.
Additionally, carbon nanofoams have also been used to create extremely efficient aerosol filters. Using cellulose nanofibers collected from recycled milk jugs, researchers were able to develop a carbon nanofoam that achieved a very high filtration efficacy (>99.5%) in tests run with 0.7 wt% nanofoam sample for particles smaller than 360 nm.
The CNTs and metal powders are mixed by a process of mechanical alloying/blending and then are compressed to form a green compact, which is then sintered to get the final product. Metallic compacts are subject to oxidation as compared to ceramics and hence the sintering has to be done in an inert atmosphere or under vacuum. [ 7 ]
A nanofiber has two external dimensions in the nanoscale, with nanotubes being hollow nanofibers and nanorods being solid nanofibers. A nanoplate/nanosheet has one external dimension in the nanoscale, [ 20 ] and if the two larger dimensions are significantly different it is called a nanoribbon .
The presence of metal impurities can be problematic for many applications. Especially catalyst metals like nickel, cobalt or yttrium may be of toxicological concern. [62] While unencapsulated catalyst metals may be readily removable by acid washing, encapsulated ones require oxidative treatment for opening their carbon shell. [63]
Nanowires also show other peculiar electrical properties due to their size. Unlike single wall carbon nanotubes, whose motion of electrons can fall under the regime of ballistic transport (meaning the electrons can travel freely from one electrode to the other), nanowire conductivity is strongly influenced by edge effects. The edge effects come ...