Amorphous High-Entropy Oxides With High-Valent Metal and Oxygen-Vacancy Pairs for Thermally Stable Catalytic...

High-entropy oxides (HEOs) show great promise in heterogeneous catalysis due to their unique structural properties. However, stabilizing the amorphous structure of HEOs under high-temperature conditions remains challenging. Herein, we propose a thermodynamic synergy-driven strategy to construct the long-range disordered structure in HEO, achieving the preservation of defect-rich sites with high thermal stability. By integrating multiple metal elements with substantial atomic size differences, we construct an amorphous MnFeCoNiCuYZrO_x HEO (MYZrO_x-a), in which the high configurational entropy creates a thermodynamic barrier against amorphous-to-crystalline transition. This strategy also demonstrates both universality and scalability for synthesizing thermally stable amorphous HEOs. Combined experimental characterization and theoretical calculations reveal that MYZrO_x-a retains short‑range disorder and abundant defect sites even after calcination at 600°C. Moreover, the stabilized high‑valence metal-oxygen vacancy (M^δ+-O_v) pairs facilitate the activation of C─H bonds and oxygen species, endowing MYZrO_x-a with exceptional methane combustion activity and durability, with stable performance exceeding 200 h even under high‑humidity conditions. This work underscores the pivotal role of configurational entropy in designing amorphous HEOs and expands their potential for advanced thermocatalytic applications.