催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (1): 100-105.

• 研究论文 • 上一篇    下一篇

铁和锰的化学状态对 LaFexMnyAl12-x-yO19 催化剂上 N2O 分解的影响

田鸣1,2, 王晓东1, 朱燕燕1,2, 王军虎1, 张涛1   

  1. 1 中国科学院大连化学物理研究所, 辽宁大连 116023 2 中国科学院研究生院, 北京 100049
  • 收稿日期:2010-01-25 出版日期:2010-01-25 发布日期:2010-01-25

Influence of Chemical States of Fe and Mn on N2O Decomposition over LaFexMnyAl12-x-yO19 Catalysts

TIAN Ming1,2, WANG Xiaodong1,*, ZHU Yanyan1,2, WANG Junhu1, ZHANG Tao1,*   

  1. 1Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China 2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2010-01-25 Online:2010-01-25 Published:2010-01-25

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摘要： 以共沉淀法制备了 LaFexMnyAl12-x-yO19 六铝酸盐催化剂, 并用 X 射线衍射、扫描电镜、N2 吸附-脱附、紫外-可见漫反射光谱和穆斯堡尔谱对催化剂进行了表征, 考察了催化剂上高浓度 N2O 分解反应的性能. 结果表明, 在所考察的条件下, Mn 比 Fe 更有利于促进六铝酸盐晶相的形成. LaFexAl12-xO19 (x = 0.5, 1) 中 Fe 以 Fe3+位于六铝酸盐尖晶石结构中的四面体位和镜面层结构中的三角双锥位, 其中后者为 N2O 分解的主要活性中心. LaMnyAl12-yO19 (y = 0.5, 1) 中 Mn 优先以 Mn2+进入四面体位, 然后以 Mn3+进入尖晶石结构中的八面体位, 并成为 N2O 分解的主要活性中心.

关键词: 铁 锰 六铝酸盐 N2O, 分解 推进剂 穆斯堡尔谱

Abstract:  LaFexMnyAl12-x-yO19 hexaaluminate catalyst samples were prepared by a coprecipitation method and tested for N2O decomposition with high concentration (30%, V/V). The catalyst samples were characterized by X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption, ultraviolet-visible spectroscopy, and Mössbauer spectroscopy. The results showed that the partial substitution by Mn led to easier formation of phase-pure hexaaluminate compared with that by Fe under the investigated conditions. Fe3+ occupied both tetrahedral sites in spinel block and trigonal bipyramid sites in mirror plane for LaFexAl12-xO19 (x = 0.5, 1) hexaaluminate. Mn2+ preferentially entered tetrahedral sites at low Mn content (y = 0.5) for LaMnyAl12-yO19 hexaaluminate, whereas Mn3+ entered octahedral sites in spinel block at y = 1. The activity tests for N2O decomposition with high concentration demonstrated that Fe3+ in trigonal bipyramid sites of LaFexAl12-xO19 and Mn3+ in octahedral sites of LaMnyAl12-yO19 were the main active centers.

Key words: iron, manganese, hexaaluminate, nitrous oxide, decomposition, propellant, M鰏sbauer spectroscopy