催化学报 ›› 2012, Vol. 33 ›› Issue (7): 1109-1114.DOI: 10.1016/S1872-2067(11)60388-4

• 研究论文 • 上一篇    下一篇

Sr 取代 LaFeO3 钙钛矿的结构性质和催化性能

张晓静, 李华举, 李勇, 申文杰*   

  1. 中国科学院大连化学物理研究所催化基础国家重点实验室, 辽宁大连 116023
  • 收稿日期:2012-02-14 修回日期:2012-03-14 出版日期:2012-06-21 发布日期:2012-06-21

Structural Properties and Catalytic Activity of Sr-Substituted LaFeO3 Perovskite

ZHANG Xiaojing, LI Huaju, LI Yong, SHEN Wenjie*   

  1. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2012-02-14 Revised:2012-03-14 Online:2012-06-21 Published:2012-06-21

摘要: Sr2+对La3+的部分取代导致LaFeO3的结构性质和催化性能发生了显著变化. 钙钛矿结构由LaFeO3的正交型变成了La0.8Sr0.2FeO3的近立方型. 由于电荷补偿效应, Sr2+取代La3+导致部分Fe3+氧化为Fe4+, 同时产生氧空穴,因而提高了La0.8Sr0.2FeO3的还原性能. 由于氧空穴的作用, La0.8Sr0.2FeO3催化剂在?CO?氧化和CH4燃烧反应中均表现出较LaFeO3高的催化活性. 在CO氧化反应中, 氧空穴有利于反应物分子的吸附并加速了气相氧分子在表面上的解离; 而在CH4燃烧反应中, 氧空穴则促进了晶格氧物种从体相到表面的扩散.

关键词: 钙钛矿, 铁酸镧, 取代, 还原性, 一氧化碳氧化, 甲烷燃烧

Abstract: Partial substitution of La3+ by Sr2+ in LaFeO3 resulted in significant changes in its structure and catalytic activity. The perovskite structure was changed from orthorhombic in LaFeO3 to nearly cubic in La0.8Sr0.2FeO3. Replacement of La3+ by Sr2+ induced a positive charge deficiency that was compensated for by the oxidation of some Fe3+ to Fe4+ and the generation of oxygen vacancies, which greatly promoted the reducibility of the perovskite. La0.8Sr0.2FeO3 gave considerably enhanced activity in CO oxidation and methane combustion because the oxygen vacancies accelerated the dissociation of gaseous oxygen on the surface in CO oxidation and facilitated the diffusion of lattice oxygen from the bulk to the surface during CH4 combustion.

Key words: perovskite, lanthanum ferrite, substitution, reducibility, carbon monoxide oxidation, methane combustion