Advances on multi-dimensional high-entropy alloy nanoarchitectures: Unconventional strategies and prospects

High-entropy alloys (HEAs) inspire exploration toward vast compositional space, enabled through the mixing of multiple elements for the advent of novel materials. Moreover, the unique blend of multiple elements into an alloy form at nanoscale in various morphologies can offer exceptional functionalities with high stability that can significantly tune the physical and chemical properties of the HEAs. However, the combination of multiple elements and their downsizing to multi-dimensional complex alloy nanostructures with limitless combinations and compositions remains highly rewarding yet intricate. Several strategies have been introduced and demonstrated to widen the scope of multi-element alloys as zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) nanostructures and exemplify their potential as promising materials for various applications. Nevertheless, these are few and insufficient in terms of element combinations, which are mainly limited to noble metals, and dimensionality, mainly as 0D nanoparticles (NPs). This review focuses on key developments and overviews elegant strategies for the development of HEA nanoarchitectures. We predict that these developments will inspire researchers to extend their work, beyond 0D HEA NPs, toward various distinct HEA morphologies with unlimited element combinations, which can provide new avenues for emerging applications and unknown technologies. Finally, we believe that this review can offer future directions and scope for the design and development of new families of HEA nanoarchitectures with vast compositional space in distinct shapes for various unattempted applications using many unexplored methodologies.