Carbon nanofibres (CNFs) are long, fibrous carbon layers in which the individual layers are arranged perpendicular to the fibre axis (platelet type) or are nested inside one another at an angle (herringbone type). They have a similar aspect ratio (ratio of length to diameter) to that of the carbon nanotubes but are significantly larger, with a diameter in the range of 150–300 nm.
Carbon nanofibres are produced catalytically in the CVD process. Depending on the catalyst used, either predominantly the platelet type or the herringbone type is formed.
Because of their irregular surface structure, with a large number of corners and edges, carbon nanofibres are an ideal material for fast adsorption/desorption processes and are often also used as a nanostructured catalyst and catalyst carrier. Especially due to the combination of catalytic activity with their inherent high electrical and thermal conductivity, they offer attractive possibilities for use in catalytic processes.
Metallic intermediate layers applied between the graphene layers improve the binding of CNFs to ceramic and metallic matrices; nanofibres modified in this way are therefore also well suited to be used in composite materials. Moreover, platelet CNFs can also be used effectively in self-lubricating materials.