In Situ Modulation of A‐Site Vacancies in LaMnO3.15 Perovskite for Surface Lattice Oxygen Activation and Boosted Redox Reactions

Abstract Modulation of A‐site defects is crucial to the redox reactions on ABO 3 perovskites for both clean air application and electrochemical energy storage. Herein we report a scalable one‐pot strategy for in situ regulation of La vacancies (V La ) in LaMnO 3.15 by simply introducing urea in the traditional citrate process, and further reveal the fundamental relationship between V La creation and surface lattice oxygen (O latt ) activation. The underlying mechanism is shortened Mn−O bonds, decreased orbital ordering, promoted MnO 6 bending vibration and weakened Jahn–Teller distortion, ultimately realizing enhanced Mn‐3d and O‐2p orbital hybridization. The LaMnO 3.15 with optimized V La exhibits order of magnitude increase in toluene oxidation and ca. 0.05 V versus RHE (reversible hydrogen electrode) increase of half‐wave potential in oxygen reduction reaction (ORR). The reported strategy can benefit the development of novel defect‐meditated perovskites in both heterocatalysis and electrocatalysis.