Au@Rh core-shell nanoparticles with dendritic structure

The Au@Rh core-shell nanoparticles (NPs) with Rh depositing on the spherical Au NPs were synthesized for the first time using successive reduction method. Au NPs were prepared by reducing HAuCl4 with l-ascorbic acid as the reducing agent and cetyltrimethylammonium bromide (CTAB) as the capping agent. Au@Rh NPs were then obtained by reducing RhCl3 in the presence of the pre-synthesized Au NPs. The morphology of the Au@Rh NPs is dendritic. Au@Rh NPs with molar ratios Au:Rh of 5:1, 2:1, 1:1 and 1:2 show that the Rh shell is polycrystalline and the growth of Rh on the Au NPs is heterogeneous nucleation.