Ordered Mesoporous High-Entropy Intermetallics for Efficient Oxygen Reduction Electrocatalysis

High-entropy alloys (HEAs) have offered wide opportunities for materials discovery, property optimization, and application exploration. In spite of some encouraging progress, manipulating HEAs with functional morphology/mesostructure and controlled chemical orderliness remains a big challenge. In this manuscript, a powerful and general strategy to synthesizing libraries of mesoporous high-entropy intermetallics (MHEIs) with controlled orderliness in both mesoscopic and atomic levels is reported for the first time. Final products feature an ordered polyhedral morphology and double-gyroid mesostructure as well as long-range L10 intermetallic phase and HEA composition, delivering multiple advantages for enhancing electrochemical performance in oxygen reduction reaction (ORR) and single rechargeable zinc-air battery. Specifically, MHEI-PtPdFeCoNi affords remarkable ORR activity (0.63 A mg-1 for mass activity and 1.01 mA cm-2 for specific activity) and superior stability (approximate to 87% activity retained for 50 000 cycles and chronoamperometry tests) compared with the MHEAs with disordered atomic arrangement and commercial Pt/C. The excellent performance comes from the optimized surface HEA multimetallization as well as ordered intermetallic and mesoporous structure that changes the chemisorption of O*/OH* intermediates and lowers the overall energy barrier of oxygen reduction. Mesoporous high-entropy intermetallics (MHEIs) with well-defined morphology/mesostructure and controlled atomic orderliness are successfully prepared, for the first time, through a modified concurrent template strategy. Benefiting from multiple structure advantages, MHEIs with an ordered intermetallic structure delivere remarkable electrocatalytic activity and superior stability in alkaline oxygen reduction reaction and single rechargeable zinc-air battery compared to its counterpart with disordered atomic arrangement and commercial Pt/C.image