Defect Engineering of High-Entropy Oxides for Superior Catalytic Oxidation Performance.

High-entropy oxides (HEOs) are crucial in various fields (power storage/conversion, electronic devices, and catalysis) owing to their adjustable structural characteristics, fabulous stability, and massive components. However, the current strategies for synthesizing HEOs suffer from low surface area and limited active sites. Herein, we present a salt-assisted strategy with remarkable universality for the preparation of HEOs with high surface area [e.g., HP-(FeCrCoNiCu) x O y : 59 m 2 /g, HP-(ZnMgNiCuCo) x O y : 49 m 2 /g, and HP-(CrMnFeNiZn) x O y : 11 m 2 /g], where HP means high porosity. Especially, HP-(FeCrCoNiCu) x O y with rich-oxygen vacancies promotes catalytic efficiency for hydrocarbon and alcohol oxidation owing to its hierarchical texture and massive oxygen vacancies. Furthermore, density functional theory is utilized to well illustrate the relationship of the structure and catalytic efficiency within the catalysts. This work offers realistic pathway for the large-scale application of HEOs in catalytic areas.