物理化学学报 >> 2014, Vol. 30 >> Issue (12): 2300-2306.doi: 10.3866/PKU.WHXB201409291

催化和表面科学 上一篇    下一篇

铁铜双金属催化剂选择性催化氧化氨为氮气

孙萌萌, 曹毅, 兰丽, 邹莎, 房志涛, 陈耀强   

  1. 四川大学化学学院, 教育部绿色化学重点实验室, 成都 610064
  • 收稿日期:2014-06-16 修回日期:2014-09-29 发布日期:2014-11-27
  • 通讯作者: 陈耀强 E-mail:nic7501@scu.edu.cn
  • 基金资助:

    国家自然科学基金(21173153), 国家高技术研究发展计划项目(863) (2013AA065304)及四川省科技厅科技支撑项目(2011GZ0035, 2012FZ0008)资助

Selective Catalytic Oxidation of Ammonia to Nitrogen over Iron and Copper Bimetallic Catalysts

SUN Meng-Meng, CAO Yi, LAN Li, ZOU Sha, FANG Zhi-Tao, CHEN Yao-Qiang   

  1. Key Laboratory of Green Chemistry & Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
  • Received:2014-06-16 Revised:2014-09-29 Published:2014-11-27
  • Contact: CHEN Yao-Qiang E-mail:nic7501@scu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21173153), National High-Tech Research and Development Program of China (863) (2013AA065304), and Major Research Program of Sichuan Province Science and Technology Department, China (2011GZ0035, 2012FZ0008).

摘要:

固定铜铁的总质量不变, 采用共浸渍法制备铜铁双金属催化剂. 为了更好地了解催化剂的性质, 分别用N2吸附-脱附、H2-程序升温还原(H2-TPR)、NH3-程序升温脱附(NH3-TPD)、X射线衍射(XRD)和X射线光电子能谱(XPS)方法对制备的催化剂进行表征. 研究发现在100000 h-1空速下, 铜铁双金属催化剂呈现出好的活性和氮气选择性. 在低温区, 随着铜含量的增加, 活性和氮气的选择性增加, 然而在高温区氮气的选择性直接和铁的含量相关. 其中催化剂Fe0.25Cu0.75/ZSM-5, 在350℃氨的转化率达到最高, 在300℃氮气的选择性上升到97%. Fe0.75Cu0.25/ZSM-5 在500 ℃有很高的氮气选择性甚至可以达到98%. 并且所有的催化剂均产生很少的N2O副产物. 表征结果显示催化剂的酸量和铜物种的含量可以影响催化剂的活性, 并且高的还原能力和铁含量有助于高温氮气选择性的提高.

关键词: 铁, 铜, 分子筛, 氨氧化反应, N2选择性, 催化剂

Abstract:

Iron and copper bimetallic catalysts with fixed total contents of copper and iron were prepared by a co-impregnation method, and then used for selective catalytic oxidation of ammonia to nitrogen. The properties of the catalysts were characterized by N2 adsorption-desorption, H2 temperature-programmed reduction (H2- TPR), NH3 temperature-programmed desorption (NH3-TPD), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The iron and copper bimetallic catalysts exhibited good activity and high selectivity of N2 at the gas hourly space velocity (GHSV) of 100000 h-1. The activity and N2 selectivity in the low temperature range increased with increasing Cu loading, whereas in the high temperature range (above 400 ℃) the selectivity of N2 was directly related to the content of iron. The highest NH3 conversion was achieved at about 350℃ for Fe0.25Cu0.75/ZSM-5, and the N2 selectivity was up to 97% at 300 ℃. On the other hand, the extremely high N2 selectivity about 98% was obtained over Fe0.75Cu0.25/ZSM-5 at 500 ℃. In addition, N2O as the by-product and greenhouse gas was obtained in very low amounts for all the catalysts. The characterization results showed that the activity was influenced by the acid content and the amounts of copper species. Moreover, the highly reducing capacity could improve the N2 selectivity.

Key words: Iron, Copper, Molecular sieve, Ammonia oxidation reaction, N2 selectivity, Catalyst

MSC2000: 

  • O643