Building carbon structures inside hollow carbon spheres.

The synthesis and characterization of helical carbon nanofibers (CNFs) contained within a fully confined nanoreactor is described. In particular, hollow carbon spheres (od = ca. 310 nm; wall thickness ca. 20 nm) were infiltrated with Cu ions (1%) to produce CuO particles (<10 nm) and the CuO was converted to Cu particles at temperature of 300 °C. Acetylene was then used as a carbon source to grow helical CNFs within the hollow carbon spheres. The diameter and helicity of the CNFs was influenced by the Cu content within a hollow carbon sphere, the limited Cu sintering inside a sphere as well as the dimensions of the sphere. The procedures employed suggest that the philosophy of building other structures (and molecules) with any elements within confined nanoreactors is possible.