Construction of AuPdPt spherical nanodendrites with a multilayered structure by manipulating etching and regrowth in seeded growth

Etching and regrowth are two typical processes involved during wet-chemical synthesis of noble-metal nanocrystals. In the present study, we demonstrate that by rationally manipulating the two processes, trimetallic nanocrystals with a unique multilayered structure can be successfully prepared in high purity, as well as with tunable sizes. In particular, by conducting co-reduction of Pd and Pt precursors in the presence of spherical Au seeds, the continuous etching of Pt(iv) ions as enabled by insufficient reducing power, together with the regrowth of Au and Pd atoms during the growth stage, allows the resultant products to exhibit a multi-layered elemental distribution, where Pd and Pt are in the inner shell while Au and Pt are dominant in the outer shell. When supported on carbon and used as electrocatalysts, these AuPdPt multilayered nanodendrites with controlled sizes in the range of 32-88 nm show an improved electrocatalytic activity and long-term durability for formic acid oxidation, as compared to commercial Pt/C. The present study offers a facile method to prepare tri-metallic nanocrystals with a controlled shape and spatial elemental distribution, which could be further extended to other noble metals or alloys.