Zhang Xianhua, Pei Chunlei, Chang Xin, Chen Sai, Liu Rui, Zhao Zhi-Jian, Mu Rentao, Gong Jinlong
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering & Technology, Collaborative Innovation Center for Chemical Science & Engineering, Tianjin University, Tianjin 300072, P. R. China.
Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City 350207, Fuzhou, P. R. China.
J Am Chem Soc. 2020 Jul 1;142(26):11540-11549. doi: 10.1021/jacs.0c04643. Epub 2020 Jun 16.
Modulating lattice oxygen in metal oxides that conducts partial oxidation of methane in balancing C-H activation and syngas selectivity remains challenging. This paper describes the discovery of distorting FeO octahedra in LaCeFeO ( = 0, 0.25 0.5, 0.75, 1) orthorhombic perovskites for the promotion of lattice oxygen activation. By combined electrical conductivity relaxation measurements and density functional theory calculations studies, this paper describes the enhancement of FeO octahedral distortion in LaCeFeO promoting their bulk oxygen mobility and surface oxygen exchange capability. Consequently, LaCeFeO with the highest FeO distortion achieves exceptional syngas productivity of ∼3 and 8 times higher than LaFeO and CeFeO, respectively, in CH partial oxidation step with simultaneous high CO conversion (92%) in the CO-splitting step at 850 °C. The results exemplify the feasibility to tailor the active lattice oxygen of perovskite by modulating the distortion of BO in ABO, which ultimately influences their reaction performance in chemical looping processes.
在进行甲烷部分氧化以平衡C-H活化和合成气选择性的金属氧化物中调节晶格氧仍然具有挑战性。本文描述了在LaCeFeO（ = 0、0.25、0.5、0.75、1）正交钙钛矿中扭曲FeO八面体以促进晶格氧活化的发现。通过结合电导率弛豫测量和密度泛函理论计算研究，本文描述了LaCeFeO中FeO八面体畸变的增强，促进了它们的体相氧迁移率和表面氧交换能力。因此，具有最高FeO畸变的LaCeFeO在850°C的CH部分氧化步骤中实现了异常高的合成气生产率，分别比LaFeO和CeFeO高约3倍和8倍，同时在CO裂解步骤中具有高CO转化率（92%）。结果例证了通过调节ABO中BO的畸变来定制钙钛矿活性晶格氧的可行性，这最终影响了它们在化学循环过程中的反应性能。
