Graphitic hollow carbon calabashes

Graphitic carbon calabashes, a new structure of carbon, have been found among the solid carbon spheres synthesized by a mixed-valent oxide-catalytic carbonization (MVOCC) process. The calabashes are as large as 0.8 μm and are constructed by graphitic carbon shells of thicknesses ∼10 nm. The calabash can be hollow or filled with a carbon core. Oxygen gas has been found to be trapped inside the calabashes, suggesting they could be used for gas/energy storage.