Kinetic-Controlled Ultrafast Synthesis of Ordered Intermetallic Nanoparticles

The disorder-order transition of metal alloys delivers ordered intermetallic nanoparticles (NPs) as efficient and stable catalysts. However, this transition is practically challenging due to the thermodynamically low driving force and the complex kinetic competition with concurrent processes (e.g., phase separation). Here, we report a kinetic-controlled phase-capturing strategy for ordering multimetallic NPs via pulsed heating treatment. This strategy enables the rapid and universal synthesis of intermetallic NPs with varying elemental compositions (up to eight elements) and stoichiometric ratios in seconds (<10 pulses, down to 1 pulse). In situ transmission electron microscopy reveals a multistep transformation pathway, where disordered NPs premelt at the heating stage of each pulse and subsequently recrystallize toward metastable intermediate states or the final ordered structures via short-range atomic diffusion in the cooling stage. This work develops a promising concept for controllably synthesizing complex intermetallic NPs, as well as for obtaining versatile metastable structures in nanomaterials.