High-entropy-alloy nanoparticles

High-entropy-alloy Nanoparticles (HEA-NPs) are nanoparticles having four or more elements alloyed in a single-phase solid solution structure. HEA-NPs possess a wide range of compositional library, distinct alloy mixing structure, and nanoscale size effect, enabling their huge potential in catalysis, energy, environmental and biomedical applications. 
Enabling synthesis.
HEA-NPs are a structural analog to bulk HEA but synthesized at the nanoscale. The formation of HEAs requires a high temperature for multi-element mixing; however, high temperature is against nano-material synthesis due to high temperature-induced structure aggregation and surface reconstruction. 
In 2018, HEA-NPs were firstly synthesized by a carbothermal shock synthesis. The carbothermal shock employs a rapid high temperature heating (e.g. 2000 K, in 55 ms) to enable the non-equilibrium synthesis of HEA-NPs with uniform size and homogeneous mixing despite containing immiscible combinations. The material and technology are also patented. Later, other similar non-equilibrium “shock” methods were also introduced to synthesize HEA-NPs and other types of high entropy nanostructures.
Properties and applications.
HEA-NPs have a large compositional library, which enables tunability in chemical composition, structure, and associated properties. In addition, owing to the high entropy structure, HEA-NPs typically show improved structural stability. With the above merits, HEA-NPs have been used as high-performance catalysts for both thermochemical and electrochemical reactions, such as ammonia oxidation, decomposition, and water splitting. High throughput and data mining approaches toward accelerated material discovery in the multi-dimensional space on HEA-NPs.