The Micron‐Droplet‐Confined Continuous‐Flow Synthesis of Freestanding High‐Entropy‐Alloy Nanoparticles by Flame Spray Pyrolysis

Alloying multiple immiscible elements into a nanoparticle with single‐phase solid solution structure (high‐entropy‐alloy nanoparticles, HEA‐NPs) merits great potential. To date, various kinds of synthesis techniques of HEA‐NPs are developed; however, a continuous‐flow synthesis of freestanding HEA‐NPs remains a challenge. Here a micron‐droplet‐confined strategy by flame spray pyrolysis (FSP) to achieve the continuous‐flow synthesis of freestanding HEA‐NPs, is proposed. The continuous precursor solution undergoes gas shearing and micro‐explosion to form nano droplets which act as the micron‐droplet‐confined reactors. The ultrafast evolution (