Graphitic structure and surface chemical activity of nanosize carbon spheres Original Research Article

Monodispersed nanosize carbon spheres have recently been synthesized using a mixed-valent oxide-catalytic carbonization (MVOCC) process. In this paper, a high surface porosity of carbon spheres produced by an interaction with WO3 is reported. The interaction mechanism is due to the reduction of WO3 to W driven by an internal Auger decay process under the stimulation of a high-energy electron beam in a transmission electron microscope; combination of the desorbed O with C results in the loss of local carbon species. This process occurs only for the atoms located at the surface and surface diffusion plays a dominant role. Closed shell “onion-like” concentric fullerenes have been observed, with a C60 molecule at the center. It is suggested that W atom(s) may also be trapped within the C60 cage. The spiral growth model proposed for the growth of large fullerenes and carbon spheres has been directly proved experimentally. High-resolution electron images suggest the presence of single-shell toroidal fullerenes.