化学学报 ›› 2009, Vol. 67 ›› Issue (15): 1749-1753. 上一篇    下一篇

研究论文

Cr/MSU-1催化剂中Cr含量对CO2氧化丙烷脱氢反应催化性能的影响

柳海涛a,b 李会泉*,a,b 杨玮娇a,c 王兴瑞a,c 张 懿a,b

  

  1. (a中国科学院过程工程研究所 绿色过程与工程重点实验室 北京 100190)
    (b中国科学院过程工程研究所 湿法冶金清洁生产技术国家工程实验室 北京 100190)
    (c中国科学院研究生院 北京 100049)

  • 收稿日期:2008-10-20 修回日期:2009-02-11 出版日期:2009-08-14 发布日期:2009-08-14
  • 通讯作者: 李会泉

Effect of Cr Content on Catalytic Performance of Cr/MSU-1 Catalysts in Oxidative Dehydrogenation of Propane to Propylene with CO2

Liu, Haitao a,b Li, Huiquan* ,a,b Yang, Weijiao a,c Wang, Xingrui a,c Zhang, Yi a,b   

  1. (a Key Laboratory for Green Process and Engineering, Institute of Process and Engineering, Chinese Academy of Sciences,
    Beijing 100190)
    (b Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process and Engineering,
    Chinese Academy of Sciences, Beijing 100190)
    (c Graduate University of Chinese Academy of Sciences, Beijing 100049)
  • Received:2008-10-20 Revised:2009-02-11 Online:2009-08-14 Published:2009-08-14
  • Contact: Li, Huiquan

研究了CO2氧化丙烷脱氢制丙烯高效wCr/MSU-1 (w=2, 4, 6, 8, 10, 质量分数, 以Cr2O3计算)催化剂中Cr含量对催化剂结构和催化活性的影响. 催化剂活性评价结果表明, 随Cr含量的增加, 催化剂的活性呈现先提高后降低的变化趋势. 在600 ℃条件下, 6.0Cr/MSU-1表现出最佳的催化反应活性, 其中丙烷、CO2转化率分别达到62.6%和22.1%. 为明确Cr含量对催化剂结构的具体影响, 对催化剂样品进行了XRD, UV-Vis和XPS表征: 催化剂样品的XRD表征发现Cr/MSU-1催化剂不仅能够保持良好的MSU-1分子筛的孔道结构, 而且活性金属Cr在载体表面具有很高的分散度, 随着Cr含量的增加催化剂表面形成明显的Cr2O3晶相; UV-Vis表征结果证实低Cr含量催化剂表面主要以Cr6+的形式存在, 高Cr含量催化剂表面有明显的Cr3+出现; 反应前后的催化剂XPS表征结果进一步证实催化剂表面的Cr6+与催化反应活性具有良好对应关系. 基于上述结果, 我们认为Cr6+是该催化剂重要的活性中心.

关键词: Cr/MSU-1催化剂, 氧化脱氢, CO2, 丙烷, 丙烯

The effects of Cr content on the catalyst structure and catalytic activities have been investigated over Cr/MSU-1 catalyst for oxidative dehydrogenation of propane to propylene with CO2. The wCr/MSU-1 catalysts [w=2.0, 4.0, 6.0, 8.0, 10.0, the quality fraction in the percentage (calculated in Cr2O3)] were evaluated and characterized with X-ray diffraction (XRD), diffuse reflectance UV-Vis and X-ray spectroscopy (XPS) techniques. The activity investigation results show that the best catalytic activity, 62.6% of propane conversion with 22.1% of CO2 conversion, were obtained on 6.0Cr/MSU-1 catalyst at 600 ℃. The XRD characterization found that Cr/MSU-1 catalysts could maintain good MSU-1 pore structure and the high dispersion of Cr on catalyst surface. With increasing the Cr content the Cr2O3 crystal was detected on the catalyst surface. UV-Vis characterization results confirmed that Cr in the low content on the catalyst surface existed mainly in the form of Cr6+, whereas it existed mainly in the form of Cr3+ in the high Cr content catalysts. The characterization results of XPS for the fresh and used catalyst further confirmed that the content of Cr6+ had a good relationship with the catalytic activity. Based on these studies, Cr6+ was considered the active sites for this reaction.

Key words: Cr/MSU-1 catalyst, oxidative dehydrogenation, carbon dioxide, propane, propylene