High-entropy nanoparticles: Synthesis-structure-property relationships and data-driven discovery

Abstract

High-entropy nanoparticles have become a rapidly growing area of research in recent years. Because of their multielemental compositions and unique high-entropy mixing states (i.e., solid-solution) that can lead to tunable activity and enhanced stability, these nanoparticles have received notable attention for catalyst design and exploration. However, this strong potential is also accompanied by grand challenges originating from their vast compositional space and complex atomic structure, which hinder comprehensive exploration and fundamental understanding. Through a multidisciplinary view of synthesis, characterization, catalytic applications, high-throughput screening, and data-driven materials discovery, this review is dedicated to discussing the important progress of high-entropy nanoparticles and unveiling the critical needs for their future development for catalysis, energy, and sustainability applications.

Abstract

BACKGROUND

High-entropy nanoparticles contain more than four elements uniformly mixed into a solid-solution structure, offering opportunities for materials discovery, property optimization, and advanced applications. For example, the compositional flexibility of high-entropy nanoparticles enables fine-tuning of the catalytic activity and selectivity, and high-entropy mixing offers structural stability under harsh operating conditions. In addition, the multielemental synergy in high-entropy nanoparticles provides a diverse range of adsorption sites, which is ideal for multistep tandem reactions or reactions that require multifunctional catalysts. However, the wide range of possible compositions and complex atomic arrangements also create grand challenges in synthesizing, characterizing, understanding, and applying high-entropy nanoparticles. For example, controllable synthesis is challenging given the different physicochemical properties within the multielemental compositions combined with the small size and large surface area. Moreover, random multielemental mixing can make it difficult to precisely characterize the individual nanoparticles and their statistical variations. Without rational understanding and guidance, efficient compositional design and performance optimization within the huge multielemental space is nearly impossible.

ADVANCES

The comprehensive study of high-entropy nanoparticles has become feasible because of the rapid development of synthetic approaches, high-resolution characterization, high-throughput experimentation, and data-driven discovery. A diverse range of compositions and material libraries have been developed, many by using nonequilibrium “shock”–based methods designed to induce single-phase mixing even for traditionally immiscible elemental combinations. The nanomaterial types have also rapidly evolved from crystalline metallic alloys to metallic glasses, oxides, sulfides, phosphates, and others. Advanced characterization tools have been used to uncover the structural complexities of high-entropy nanoparticles. For example, atomic electron tomography has been used for single-atom-level resolution of the three-dimensional positions of the elements and their chemical environments. Finally, high-entropy nanoparticles have already shown promise in a wide range of catalysis and energy technologies because of their atomic structure and tunable electronic states. The development of high-throughput computational and experimental methods can accelerate the material exploration rate and enable machine-learning tools that are ideal for performance prediction and guided optimization. Materials discovery platforms, such as high-throughput exploration and data mining, may disruptively supplant conventional trial-and-error approaches for developing next-generation catalysts based on high-entropy nanoparticles.

OUTLOOK

High-entropy nanoparticles provide an enticing material platform for different applications. Being at an initial stage, enormous opportunities and grand challenges exist for these intrinsically complex materials. For the next stage of research and applications, we need (i) the controlled synthesis of high-entropy nanoparticles with targeted surface compositions and atomic arrangements; (ii) fundamental studies of surfaces, ordering, defects, and the dynamic evolution of high-entropy nanoparticles under catalytic conditions through precise structural characterization; (iii) identification and understanding of the active sites and performance origin (especially the enhanced stability) of high-entropy nanoparticles; and (iv) high-throughput computational and experimental techniques for rapid screening and data mining toward accelerated exploration of high-entropy nanoparticles in a multielemental space. We expect that discoveries about the synthesis-structure-property relationships of high-entropy nanoparticles and their guided discovery will greatly benefit a range of applications for catalysis, energy, and sustainability.

Diversifying nanoparticles

Multielement nanoparticles are attractive for a variety of applications in catalysis, energy, and other fields. A more diverse range and larger number of elements can be mixed together because of high-entropy mixing states accessed by a number of recently developed techniques. Yao et al . review these techniques along with characterization methods, high-throughput screening, and data-driven discovery for targeted applications. The wide range of different elements that can be mixed together presents a large number of opportunities and challenges. —BG

Abstract

A review highlights improvements in synthesizing and stabilizing multielement nanoparticles.