Cooperative Catalysis toward Oxygen Reduction Reaction under Dual Coordination Environments on Intrinsic AMnO 3 ‐Type Perovskites via Regulating Stacking Configurations of Coordination Units

2020 
It remains challenging for pure-phase catalysts to achieve high performance during the electrochemical oxygen reduction reaction to overcome the sluggish kinetics without the assistance of extrinsic conditions. Herein, a series of pristine perovskites, i.e., AMnO3 (A = Ca, Sr, and Ba), are proposed with various octahedron stacking configurations to demonstrate the cooperative catalysis over SrMnO3 jointly explored by experiments and first-principles calculations. Comparing with the unitary stacking of coordination units in CaMnO3 or BaMnO3 , the intrinsic SrMnO3 with a mixture of corner-sharing and face-sharing octahedron stacking configurations demonstrates superior activity (Ehalf-wave  = 0.81 V), and charge-discharge stability over 400 h without the voltage gap (≈0.8 V) increasing in zinc-air batteries. The theoretical study reveals that, on the SrMnO3 (110) surface, the active sites switch from coordinatively unsaturated atop Mn (*OO, *OOH) to Mn-Mn bridge (*O, *OH). Therefore, the intrinsic dual coordination environments of Mn-Ocorner and Mn-Oface enable cooperative modulation of the interaction strength of the oxygen intermediates with the surface, inducing the decrease of the *OH desorption energy (rate-limiting step) unrestricted by scaling relationships with the overpotential of ≈0.28 V. This finding provides insights into catalyst design through screening intrinsic structures with multiple coordination unit stacking configurations.
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