Palladium Zinc Nanocrystals: Nanoscale Amalgamation Enables Multifunctional Intermetallic Colloids

Abstract

AbstractIntermetallic nanocrystals are emerging materials for energy, catalysis, and biomedical applications, but combining two or more metals at the nanoscale remains challenging. The amalgamation reaction represents a convenient method for hundreds of intermetallic compositions, as it relies on fast and efficient alloying of liquid metals into presynthesized metallic seeds. Here, Pd–Zn nanocrystals, prepared via Zn amide thermolysis on the surface of Pd nanocrystals and subsequent amalgamation alloying, are investigated. Size‐uniform nanocrystals and control over a wide range of Pd–Zn compositions are achieved. This allows deriving a phase diagram at the nanoscale, in which miscibility gaps and three phases with broad solid solutions are detected. Furthermore, the formation of homogeneous ZnO shells for Pd–Zn compositions extending beyond phase solubility limits is observed. Full chemistry control for Pd–Zn nanocrystals enables a rational choice of materials for selected energy applications, achieveing an extended lifetime of Zn‐ion batteries for Zn‐rich PdZn2 stoichiometry, superior electrocatalytic properties for nearly stoichiometric PdZn halite phase, and the stability and efficiency of high‐voltage cathodes benefiting from ZnO shell protection around Pd3Zn10 nanocrystals are reported. This paper exemplifies the multifunctionality of intermetallics Pd–Zn nanocrystals, while this methodology can be extended to many other bimetallic nanomaterials.