Subsurface A-site vacancy activates lattice oxygen in perovskite ferrites for methane anaerobic oxidation to syngas

Autor: Jiahui He, Tengjiao Wang, Xueqian Bi, Yubo Tian, Chuande Huang, Weibin Xu, Yue Hu, Zhen Wang, Bo Jiang, Yuming Gao, Yanyan Zhu, Xiaodong Wang
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Nature Communications, Vol 15, Iss 1, Pp 1-11 (2024)
Druh dokumentu: article
ISSN: 2041-1723
DOI: 10.1038/s41467-024-49776-y
Popis: Abstract Tuning the oxygen activity in perovskite oxides (ABO3) is promising to surmount the trade-off between activity and selectivity in redox reactions. However, this remains challenging due to the limited understanding in its activation mechanism. Herein, we propose the discovery that generating subsurface A-site cation (Lasub.) vacancy beneath surface Fe-O layer greatly improved the oxygen activity in LaFeO3, rendering enhanced methane conversion that is 2.9-fold higher than stoichiometric LaFeO3 while maintaining high syngas selectivity of 98% in anaerobic oxidation. Experimental and theoretical studies reveal that absence of Lasub.-O interaction lowered the electron density over oxygen and improved the oxygen mobility, which reduced the barrier for C-H bond cleavage and promoted the oxidation of C-atom, substantially boosting methane-to-syngas conversion. This discovery highlights the importance of A-site cations in modulating electronic state of oxygen, which is fundamentally different from the traditional scheme that mainly credits the redox activity to B-site cations and can pave a new avenue for designing prospective redox catalysts.
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