X.Q. Liu#, J.X. Mi#, L. Shi, H.Y. Liu, J. Liu, Y. Ding, J.Q. Shi, M.H. He, Z.S. Wang, S.C. Xiong, Q.F. Zhang, Y.F. Liu, Z.-S. Wu, J.J. Chen*, J.H. Li

Angewandte Chemie, 2021, 60, 26747–26754.

DOI: 10.1002/anie.202111610 [PDF]

Modulation of A-site defects is crucial to the redox reactions on ABO3 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 (VLa) in LaMnO3.15 by simply introducing urea in the traditional citrate process, and further reveal the fundamental relationship between VLa creation and surface lattice oxygen (Olatt) activation. The underlying mechanism is shortened Mn-O bonds, decreased orbital ordering, promoted MnO6 bending vibration and weakened Jahn-Teller distortion, ultimately realizing enhanced Mn-3d and O-2p orbital hybridization. The LaMnO3.15 with optimized VLa exhibits order of magnitude increase in toluene oxidation and ~0.05 V versus RHE (reversible hydrogen electrode) increase of half-wave potential in oxygen reduction reaction (ORR). The reported simple but effective strategy for in situ modulation of La-site defects and the corresponding influence on the electronic structure of MnO6 can benefit the development of novel defect-meditated perovskites in both heterocatalysis and electrocatalysis.