Sn Galvanic Exchange Enables Creation of Trimetallic Multiphase Plasmonic Nanoparticles

Galvanic exchange is a powerful approach for transforming simple unary nanostructures into complex multimetallic architectures with enhanced properties that arise from sophisticated compositional mixing, morphology, and structure. Compared to noble metals, non-precious metals facilitate galvanic exchange with a wider range of metals, providing access to a greater diversity of nanoparticle compositions and structures. Here, we report a compositionally versatile strategy to synthesize trimetallic multiphase alloy-intermetallic nanoparticles from plasmonic Au─Sn nanoparticles. The galvanic exchange of Sn in Au─Sn nanoparticles by metal precursor solutions creates trimetallic Au─Sn─M (M = Pd, Rh, Cu) nanoparticles with tunable optical properties and textured surface morphologies. The coexisting alloy and intermetallic crystalline phases and long-range order are maintained after galvanic exchange, with synchrotron-based X-ray total scattering pair distribution function analysis quantifying the induced local lattice distortions. This work offers new insights into the compositional, morphological, and structural transformations induced by galvanic exchange across atomic and nanoscopic scales in multiphase systems.