Nanoparticles, alumina, nucleation

Many clusters of Fe atoms are formed both inside and at the surface of each alumina grain and progressively grow. When the Fe nanoparticles located at the surface of the alumina grains reach a size around 0.7-2 nm, they immediately catalyze the decomposition of CH4 and the nucleation and growth of CNTs of very small diameter ... 

FIGURE 9.9 (a) Image of Pd nanoparticles nucleated at steps and domain boundaries of an alumina film grown on NiAl(OOO). (b) Atomic resolution images of crystaUine Pd nanoparticles. The resolution is kept a few layers down the sides, allowing identification of the side facets. The dots indicate atomic positions consistent with a (111) facet, (c) Schematic representation of a crystalhne truncated cuboctahedron of Pd on an oxide surface. The various potential adsorption sites are indicated by coloring in different gray-scales. Adapted from Freund (2008). 

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