期刊
ADVANCED FUNCTIONAL MATERIALS
卷 31, 期 14, 页码 -出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/adfm.202006439
关键词
electron structure; oxygen activation; perovskite oxides; surface active site; surface segregation
类别
资金
- National Natural Science Foundation of China [21831003, 21671076, 21621001, 21801090]
- Natural Science foundation of Jilin Province [20191004020TC]
- Fundamental Research Funds for the Central Universities [3102018bzc007]
- Users with Excellence Program of Hefei Science Center CAS [2020HSC-UE002]
- China Postdoctoral Science Foundation [2019M661203]
- DOE
- SSRL
- EPSRC
- EPSRC [EP/R023816/1] Funding Source: UKRI
One of the key challenges limiting the utilization of ABO(3) perovskite oxides in heterogeneous catalysis is the dominant presence of catalytically inactive A-site cations. Engineering of B-site terminated perovskites is considered effective to address this issue, although it has not been fully successful to date. By synthesizing a Mn-terminated perovskite via a one-pot hydrothermal method, the study demonstrates improved catalytic activity and stability for CO oxidation.
For ABO(3) 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 O-2-(x). Such structural optimization significantly reduces the activation energy barriers on going from O-2(-) species to important intermediate O- species during O-2 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.
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