Combining different precious metals to generate alloy nanocrystals with desirable shapes and compositions remains a challenge. In this work, we demonstrate that Rh−Pd alloy nanorods with well-distributed and tunable compositions can be synthesized using a one-pot polyol method.

Abstract

Combining different precious metals to generate alloy nanocrystals with desirable shapes and compositions remains a challenge because of the low miscibility between these metals and/or the different reduction potentials of their salt precursors. Specifically, Rh and Pd are considered to be immiscible in the bulk solid over the entire composition range. Here we demonstrate that Rh−Pd alloy nanorods with well-distributed and tunable compositions can be synthesized using a one-pot polyol method. The success of our synthesis relies on the introduction of bromide as a coordination ligand to tune the redox potentials of Rh(III) and Pd(II) ions for the achievement of co-reduction. The atomic ratio of the Rh−Pd alloy nanorods can be facilely tuned by changing the molar feeding ratio between the two precursors. We also systematically investigate the effects of water on the morphology of the Rh−Pd alloy nanocrystals. In an attempt to promote future use of these alloy nanorods, we successfully scale up their synthesis in a continuous-flow reactor with no degradation to the product quality.