Manipulating Surface Termination of Perovskite Manganate for Oxygen Activation

Wang, Xiyang; Li, Xinbo; Chu, Xuefeng; Cao, Rui; Qian, Jingyu; Cong, Yingge; Huang, Keke; Wang, Jiaao; Redshaw, Carl; Sarangi, Ritimukta; Li, Guangshe; Feng, Shouhua

Abstract

For ABO3 perovskite oxides, one of the key issues limiting their utilization in heterogeneous catalysis is the dominant presence of catalytically inactive A‐site cations at the surface. The engineering of B‐site terminated perovskites is considered as an effective method to address this issue, especially when dealing with Mn/Co‐based perovskite catalysts. However, to date, such a strategy has not been fully successful and remains a major challenge in the field. Herein, a Mn‐terminated La0.45Sr0.45MnO3 (B‐LSM) is successfully synthesized via a one‐pot hydrothermal method, in which low‐valence Mn ions partially occupy the A site to form the active Mn‐excess phase. Experimental results and theoretical calculations reveal that the presence of the surface Mn termination in B‐LSM optimizes the hybrid orbitals of Mn 3d‐O 2p and promotes the activation of surface lattice oxygen, where the pristine inert lattice O2− is evolved into active and stable lattice O2−x. Such structural optimization significantly reduces the activation energy barriers on going from O2− species to important intermediate O− species during O2 activation. Moreover, this results in good stability and Pt‐like activity for the B‐LSM during CO oxidation. This work offers a new chemical route for the design of advanced perovskite‐type oxides possessing novel functions.

Citation

Wang, X., Li, X., Chu, X., Cao, R., Qian, J., Cong, Y., Huang, K., Wang, J., Redshaw, C., Sarangi, R., Li, G., & Feng, S. (in press). Manipulating Surface Termination of Perovskite Manganate for Oxygen Activation. Advanced Functional Materials, Article 2006439. https://doi.org/10.1002/adfm.202006439

• Journal Article Type: Article
• Acceptance Date: Jan 12, 2021
• Online Publication Date: Jan 27, 2021
• Deposit Date: Jan 27, 2021
• Publicly Available Date: Jan 28, 2022
• Journal: Advanced Functional Materials
• Print ISSN: 1616-301X
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Article Number: 2006439
• DOI: https://doi.org/10.1002/adfm.202006439
• Keywords: Electron structure; Oxygen activation; Perovskite oxides; Surface active site; Surface segregation
• Public URL: https://hull-repository.worktribe.com/output/3703263
• Publisher URL: https://onlinelibrary.wiley.com/doi/10.1002/adfm.202006439