Liquid metal for high-entropy alloy nanoparticles synthesis.

High-entropy alloy nanoparticles (HEA-NPs) show great potential as functional materials 1-3 . However, thus far, the realized high-entropy alloys have been restricted to palettes of similar elements, which greatly hinders the material design, property optimization and mechanistic exploration for different applications 4,5 . Herein, we discovered that liquid metal endowing negative mixing enthalpy with other elements could provide a stable thermodynamic condition and act as a desirable dynamic mixing reservoir, thus realizing the synthesis of HEA-NPs with a diverse range of metal elements in mild reaction conditions. The involved elements have a wide range of atomic radii (1.24-1.97 Å) and melting points (303-3,683 K). We also realized the precisely fabricated structures of nanoparticles via mixing enthalpy tuning. Moreover, the real-time conversion process (that is, from liquid metal to crystalline HEA-NPs) is captured in situ, which confirmed a dynamic fission-fusion behaviour during the alloying process.