Growth and stability of Pt on Au nanorods

We present a systematic study of Pt overgrowth on Au nanorods via a wet chemistry approach. The atomic resolved imaging provides direct evidence of initial epitaxial growth of Pt on the surface of Au nanorods, with a preferential deposition occurring at the rod ends. Over a period of one and half years, the carbon-supported nanorods are shown to have undergone a structural transformation when they are kept at ambient conditions, in contrast to the rods kept in solutions whose structure remains stable. Further controlled experiments show morphological changes of the nanorods upon annealing. We discuss the results in terms of the role that kinetics vs. thermodynamics plays in the observed phenomena.