Epitaxially Grown Heterostructured SrMn₃ O_6-x -SrMnO₃ with High-Valence Mn^3+/4+ for Improved Oxygen Reduction...

Heterostructured catalysts show outstanding performance in electrochemical reactions owing to their beneficial interfacial properties. However, the rational design of heterostructured catalysts with the desired interfacial properties and charge-transfer characteristics is challenging. Herein, we developed a SrMn₃ O_6-x -SrMnO₃ (SMO_x -SMO) heterostructure through epitaxial growth, which demonstrated excellent electrocatalyst performance for the oxygen reduction reaction (ORR). The formation of high-valence Mn^3+/4+ is beneficial for promoting a positive shift in the position of the d-band center, thereby optimizing the adsorption and desorption of ORR intermediates on the heterojunction surface and resulting in improved catalytic activity. When SMO_x -SMO was applied as an air-electrode catalyst in a rechargeable zinc-air battery, a high output voltage and power density was achieved, with performance comparable to a battery prepared with Pt/C-IrO₂ air-electrode catalysts, albeit with much better cycling stability.