A novel Co@Au structure formed in bimetallic core@shell nanoparticles.

Core@shell Co@Au nanoparticles of around 8 nm have been produced by the inert gas condensation method, revealing for the first time that most of the nanoparticles exhibit an icosahedral shape in agreement with the theoretical prediction. Additionally, we report the existence of a novel morphology which consists of a Co icosahedron surrounded by fcc Au facets, reported here for the first time.