Triggering efficient Mn active centers by tuning the localized Sr2+ sites in high-entropy ABO3 oxygen electrocatalysis

Understanding the function of individual elements in high-entropy perovskites is one of the critical issues for the design of inexpensive and efficient bifunctional electrocatalysts. Here, we report our findings in boosting the electrochemical activity and durability of a high-entropy perovskite catalyst via sequential substitution of Sr2+ for the A-site elements. According to the Sr2+ localized tuned, the catalyst of (LaSmGdSrPr)0.2MnO3 has a half-wave potential of 0.786 V vs. RHE and an overpotential of 0.378 V and has better ORR and OER electrocatalytic activity than the Sr-free high-entropy perovskite catalyst (LaSmGdYPr)0.2MnO3.This is attributed to the local doping of Sr2+ activating the active center of the high-entropy perovskite catalyst (LaSmGdSrPr)0.2MnO3, modulating the adsorption energy of the oxygen-containing intermediates and the electronic structure of the transition metal at the B-site, which results in efficient oxygen electrocatalytic activity. On the other hand, the introduction of Sr2+ enhances the hybridization between Mn 2p and O 1 s and accelerates the adsorption and desorption kinetics of the intermediates, leading to both enhanced activity and durability of (LaSmGdSrPr)0.2MnO3. DFT theoretical calculations also demonstrate the key role played by Sr2+ in the high-entropy perovskite structure for the improvement of the electrocatalytic activity. This study provides new insights for designing high-entropy electrocatalysts for various potential applications.