Air oxidation could result in the motion of metal atoms confined in carbon nanotubes, and this could be exploited in order to tailor various hybrid nanostructures. Using controlled air-oxidation, as-prepared metal-carbon nanorods could be converted first to core-shell-void nanorods, then to metal/metal oxide-carbon nanotubes and finally to mesoporous metal oxide nanotubes.

Diffusion of Metal in a Confined Nanospace of Carbon Nanotubes Induced by Air Oxidation. J.Zhou, H.Song, X.Chen, J.Huo: Journal of the American Chemical Society, 2010, 132[33], 11402-5