Nanocrystals of intermetallic compounds are a large family of emerging materials with highly promising catalytic, plasmonic, magnetic, and energy storage and conversion applications. However, a generalized synthetic approaches for intermetallic nanocrystals are lacking. Here we report the development of a colloidal synthesis based on amalgamation of monometallic nanocrystal seeds with low-melting point metals. We use this approach to achieve crystalline and compositionally uniform intermetallic nanocrystals of Au-Ga, Ag-Ga, Cu-Ga, Ni-Ga, Pd-Ga, Pd-In and Pd-Zn compounds. We demonstrate a compositional tunability across phases (e.g., AuGa2, AuGa, Au7Ga2 and Ga-doped Au nanocrystals for the bimetallic Au-Ga system), while each phase can be prepared with accurate size control and excellent size uniformity. Figure 1 illustrates the applicability of amalgamation seeded growth towards intermetallic nanocrystals with unprecedented quality and flexibility of materials design. Our new synthetic method is simple, predictive and generalizable, giving access to a large family of size and composition controlled intermetallic nanocrystals, thus opening up a multitude of possibilities for these materials.

Nanoscale amalgamation reaction as generalizable approach for size and composition uniform intermetallic nanocrystals

ACS Fall 2021

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