Controllable porous perovskite with three-dimensional ordered structure as an efficient oxygen reduction reaction electrocatalyst for flexible aluminum-air battery

Perovskite materials have recently attracted extensive attention since tailoring their chemical compositions has led to remarkable activity toward oxygen reduction reaction. However, the desired electrocatalytic activity is limited by the morphological effect, and lack of methods to achieve large surface area. Herein we report an effective strategy to synthesize three-dimensional ordered macroporous (3DOM) perovskite oxides, where La_0.75Sr_0.25MnO₃ (3DOM LSMO) displays excellent ORR activity and durability with considerable specific surface area (43.1 m² g^-1). The electrochemical results exhibit that the electron transferred numbers (n) is close to 4 and the H₂O₂ yield (% H₂O₂) is as low as 10% for 3DOM LSMO, which mainly attributes to comprehensive effect of the reduced Mn valence state, the increased specific surface, and the exposed high activity crystal planes. First-principles study confirms that the lowest overpotential obtained by LSMO is in good agreement with the experimental results. Our work demonstrates perovskite oxides with larger surface area could be advanced oxygen catalysts with wide applications.