Guiding principles for seeded electrochemical synthesis of multimetallic nanocrystals

Electrodeposition offers control over nanocrystal growth through modulation of applied current or potential, which governs precursor reduction kinetics, nucleation behaviour and local ion concentrations. However, conventional electrodeposition often yields ill-defined morphologies and aggregated nanocrystals. Here seed-assisted electrodeposition is used to overcome these limitations, enabling growth of structurally complex and compositionally well-defined multimetallic nanocrystals. We identify lattice mismatch and metal–metal bond dissociation energy as key parameters dictating the growth mode; high values of either parameter promote island-like overgrowth, while low lattice-mismatch favours layer-by-layer growth. Guided by these mechanistic insights, uniform metal shell deposition is achieved across diverse bimetallic systems, including those with substantial interfacial strain, enabling synthesis of multilayered trimetallic nanocrystals. Furthermore, the formation of hollow-shell nanocrystals is demonstrated by selective interfacial etching achieved by dynamically modulating the redox environment during growth. Collectively, these findings establish design principles for the electrochemical synthesis of core–shell nanocrystals, including multimetallic variants and hollow architectures. Conventional electrodeposition often yields ill-defined morphologies and aggregated nanocrystals. Here, by linking growth behaviour to lattice mismatch and metal–metal bond energy, seed-assisted electrodeposition enables the controlled synthesis of structurally defined multimetallic nanocrystals, including core–shell, multilayered and hollow architectures, through programmable electrochemical pathways.