The adsorption and diffusion of C atoms in Ni were studied by using density-functional theory calculations to understand the growth mechanism of C nanotubes in the initial stages. When combined with the results for surface and sub-surface diffusion, the diffusion behaviour around the edges between low-index Ni surfaces revealed that the growth of C nanotubes was related to the diffusion barriers across these edge regions of Ni nanoparticles, in addition to the growth temperature. The results were explained in terms of reaction mechanisms which were kinetically or thermodynamically controlled; depending upon the temperature at which the C nanotubes grew.

Carbon Diffusion around the Edge Region of Nickel Nanoparticles. Y.H.Shin, S.Hong: Applied Physics Letters, 2008, 92[4], 043103