High-entropy materials are mainly composed of high-entropy alloys (HEAs) and their derivates. Among them, HEAs account for a big part. As a new kind of alloy, they are now arousing great interests because of their high mechanical strength, extraordinary fracture toughness, and corrosion resistance compared with traditional alloys. These characteristics allow the use of HEAs in various fields, including mechanical manufacturing, heat-resistant, radiation-resistant, corrosion-resistant, and wear-resistant coatings, energy storage, heterocatalysis, etc. In order to promote the extensive application of HEAs, it is of significance to realize their rational design and preparation. In this paper, a systematic review focusing on the rational design and fabrication of nanosized HEAs is given. The design principles of how to match different elements in HEAs and the premise for the formation of single-phase solid solution HEAs are first illustrated. Computation methods for the prediction of formation conditions and properties of HEAs are also in discussion. Then, a detailed description and comparison of the synthesis methods of HEAs and their derivate, as well as their growing mechanism under various synthetic environments is provided. The commonly used characterization methods for the detection of HEAs, along with the typical cases of the application of HEAs in industrial materials, energy storage materials and catalytic materials are also included. Finally, the challenges and perspectives in the design and synthesis of HEAs would be proposed. We hope this review will give guidance for the future development of HEAs materials.

Because of its importance in enhancing charge separation and transfer, built-in electric field engineering has been acknowledged as an effective technique for improving photocatalytic performance. Herein, a stable p–n heterojunction of 2D/2D (2D: two-dimensional) Co₃O₄/ZnIn₂S₄ with a strong built-in electric field is precisely constructed. The Co₃O₄/ZnIn₂S₄ heterojunction exhibits a higher visible-light photocatalytic hydrogen (H₂) evolution rate than the individual components, which is primarily attributed to the synergy effect of improved light absorption, abundant active sites, short charge transport distance, and high separation efficiency of photogenerated carriers. Furthermore, the photoelectrochemical studies and density functional theory (DFT) calculation results demonstrate that the enhanced interfacial charge separation and migration induced by the generated built-in electric field are the critical reasons for the boosted photocatalytic performance. This research might pave the way for the rational design and manufacturing of 2D/2D heterojunction photocatalysts with extremely efficient photocatalytic performance for solar energy conversion.