Modification of carbon nanostructures by high energy ball-milling under argon and hydrogen atmosphere

High energy ball-milling of graphite leads to nanocrystalline structures of carbon. The structures are characterised by small crystalline particles embedded in an amorphous matrix causing a high specific surface area. To investigate and quantify these nanostructures X-ray powder diffraction, high resolution transmission electron microscopy and specific surface area measurements were used. By changing the atmosphere in milling vials from argon to hydrogen the generation of the graphitic nanostructures can be decelerated. Thereby, it is possible to modify the structures in a definite way and to receive higher specific surface areas for longer milling times. Furthermore, during milling under hydrogen atmosphere the broken carbon bonds are saturated by hydrogen. In this way, it is possible to stabilise the produced nanostructures and to prevent agglomeration.