Activation of partial metal sites in high-entropy oxides for enhancing thermal and electrochemical catalysis

High-entropy oxides (HEOs) have been tentatively and prospectively applied for chemical catalysis and energy storage. However, further enhancing their performance is difficult owing to the difficulty in precisely regulating the physical-chemical properties. In this work, a general in-situ modulation strategy of solid-phase combustion involving thiourea addition and alkali liquor treatment is developed to activate metal sites and lattice oxygen species of CuCoNiZnAl HEOs. Consequently, compared with pristine HEOs, the activated HEOs not only display higher CO2 hydrogenation and CO oxidation activities but also significantly enhanced electrocatalytic performance (discharge/charge capacities of 12049/9901 mAh/g) with excellent cycle stability (2500 h) for Li-O2 batteries. The superior performance of the activated HEOs is attributed to its facile electron transferability. This simple and effective strategy could be easily applied on a large scale, guiding the development of highly active heterogeneous HEO catalysts for various functional applications.