Ultra-high-entropy alloy nanoparticles: beyond five components

Abstract

High-entropy alloy nanoparticles (HEANPs) composed of five or more elements hold great promise for important applications, including catalysis for critical energy transformations. Although initial research focused on materials that contain five components given the challenge of alloying many elements with different properties, novel strategies developed in recent years have greatly extended the compositional space, number and diversity of elements in these alloys, thereby opening a new realm of possibilities. In this review, we focus on reports of HEANPs containing six or more components. To this end, we reviewed the theoretical framework for describing these novel high-entropy alloy materials; various synthetic methods devised to produce these materials; and their various applications, including electrocatalysis, thermocatalysis, and photothermal conversion. We conclude by providing an overview of the challenges and perspectives for future research and guidance for the progression of the field.