Controlling Redox Interplay in the Formation of Anisotropic Multimetallic Nanocrystals

Abstract Controlling the interplay between reduction and galvanic processes is critical for tailoring the structure and composition of multimetallic nanocrystals. Here, we report a synthetic strategy to produce anisotropic Au–Pd–Pt nanocrystals with tunable morphologies and elemental distributions. Platinum deposition on single-crystal Au@Pd nanorods (NRs) was modulated by varying the concentration of ascorbic acid, enabling control over the balance between reduction and galvanic-like processes. This approach yields distinct nanostructures, including nanoframes, cloud-like morphologies, and core–shell–shell architectures. Advanced electron microscopy, including high-resolution HAADF STEM imaging, EDX elemental mapping, and electron tomography, reveals intricate elemental distributions, the formation of cavities and tunnels, the apparent preservation of single-crystal characteristics in Au@Pd NRs under the explored conditions, and gold etching induced by the platinum precursor. A preliminary evaluation of catalytic activity suggests enhanced ethanol oxidation performance for nanoframe structures. These findings establish a versatile strategy for engineering anisotropic multimetallic nanocrystals through controlled redox interplay.