Bulk synthesis of carbon nanostructures: Hollow stacked-cone-helices by chemical vapor deposition

Bulk synthesis of hollow carbon stacked-cone-helices of diameter from 10 nm to 0.5 μm is reported. The fibres’ walls are made up of parallel stacked-cone-like structures with an inter-cone distance from 3.38 to 3.5 Å. Apex angles observed are in the range from 30° to 110°, suggesting that the carbon nanofibres are constructed by a single graphene sheet which forms a helical structure instead of a stacked cone or open stacked cup structure. A new 3-D construction of the stacked-cone-helix is presented. Our results show that metal Pd catalyst plays a key role in obtaining carbon products with cone-helix structure and high yield (200%). These novel fibres could be used as nano-wire templates, micro-spray, and field emitters.