物理化学学报 >> 2011, Vol. 27 >> Issue (05): 1169-1175.doi: 10.3866/PKU.WHXB20110502

催化和表面科学 上一篇    下一篇

La2CoAlO6催化剂的制备及其甲烷催化燃烧性能

张慧敏1,胡瑞生1, 胡佳楠1, 张玉龙2   

  1. 1. 内蒙古大学化学化工学院, 稀土材料化学与物理重点实验室, 呼和浩特 010021;
    2. Western Research Institute, 365 N 9St, Laramie, Wyoming, USA
  • 收稿日期:2011-01-13 修回日期:2011-03-03 发布日期:2011-04-28
  • 通讯作者: 胡瑞生 E-mail:cehrs@imu.edu.cn
  • 基金资助:

    国家自然科学基金(20763003), 教育部春晖计划(Z2007-1-01029)及内蒙古自然科学基金(2008 0404 MS 0123)资助项目

Preparation and Catalytic Activities of La2CoAlO6 for Methane Combustion

ZHANG Hui-Min1, HU Rui-Sheng1, HU Jia-Nan1, ZHANG Yu-Long2   

  1. 1. Key Laboratory of Rare Earth Materials Chemistry and Physics, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, P. R. China;
    2. Western Research Institute, 365 N 9St, Laramie, Wyoming, USA
  • Received:2011-01-13 Revised:2011-03-03 Published:2011-04-28
  • Contact: HU Rui-Sheng E-mail:cehrs@imu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20763003) and Chun Hui Plans of the Ministry of Education of China (Z2007-1-01029) and Natural Science Foundation of Inner Mongolia, China (2008 0404 MS 0123).

摘要:

采用溶胶-凝胶法, 以柠檬酸为络合剂制备了新型稀土双钙钛矿催化材料La2CoAlO6, 利用X射线粉末衍射(XRD)、H2-程序升温还原(H2-TPR)、比表面(BET)、扫描电镜(SEM)、傅里叶变换红外(FT-IR)光谱和磁性测试等手段对其进行了表征, 以甲烷催化燃烧反应为探针考察了其催化活性. 结果表明, 在空气气氛中, 经过1100 °C焙烧3 h后, 可以形成稳定的单相稀土双钙钛矿型化合物La2CoAlO6, 且该化合物表现出较好的甲烷催化燃烧活性, 起燃温度(T10)和完全转化温度(T90)分别为434.1和657.4 °C. 与稀土单钙钛矿型催化剂LaCoO3和LaAlO3相比, 其T10分别降低了56.5和138.2 °C, T90分别降低了84.6和108.9 °C. H2-程序升温还原结果表明, 稀土双钙钛矿型化合物La2CoAlO6有较低的还原温度, 并且经过H2-程序升温还原反应后, La2CoAlO6样品XRD图中的所有衍射峰均向小角度方向发生了移动. 扫描电子显微镜的结果表明, 稀土双钙钛矿型催化剂La2CoAlO6表现出无规则的片状形貌及较强的抗烧结性. 此外还发现稀土双钙钛矿型催化剂La2CoAlO6的磁滞回线较为特殊.

关键词: 稀土, 双钙钛矿, 单钙钛矿, 甲烷催化燃烧, 溶胶-凝胶法

Abstract:

A novel rare earth double perovskite-type catalyst (La2CoAlO6) was prepared by the sol-gel method using citric acid as complex agent. The catalyst was characterized by X-ray powder diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), specific surface area (BET), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and magnetic property measurement. This catalyst was evaluated for methane combustion. The results showed that a single-phase rare earth double perovskite oxide La2CoAlO6 could be formed by calcination at 1100 °C for 3 h. La2CoAlO6 gives good catalytic activity for methane combustion. It has a light-off temperature (T10) of 434.1 °C and a total conversion temperature (T90) of 657.4 °C. Compared with the single rare earth perovskite-type oxides LaCoO3 and LaAlO3, the T10 decreased by 56.5 and 138.2 °C, and T90 decreased by 84.6 and 108.9 °C, respectively. The FT-IR results indicate that all the synthesized oxides possess perovskite-type structures. Furthermore, the La2CoAlO6 samples showed excellent catalytic activity for methane combustion, which could be related to the decrease in reduction temperature that was observed in the H2-TPR experiments. This was probably because of the increased oxygen mobility that was promoted by the presence of aluminum. In addition, the rare earth double perovskite-type oxide La2CoAlO6 has a platelet morphology and is resistant to sintering. We also found that the double perovskite oxide La2CoAlO6 had special magnetic properties.

Key words: Rare earth, Double perovskite, Single perovskite, Methane catalytic combustion, Sol-gel method

MSC2000: 

  • O643