物理化学学报 >> 2015, Vol. 31 >> Issue (2): 329-336.doi: 10.3866/PKU.WHXB201412082

催化和表面科学 上一篇    下一篇

Cu-SSZ-13/堇青石整体式催化剂的原位合成及其NH3选择性催化还原NO性能

张宇, 王红宁, 陈若愚   

  1. 常州大学石油化工学院, 江苏 常州 213164
  • 收稿日期:2014-10-09 修回日期:2014-12-08 发布日期:2015-01-26
  • 通讯作者: 陈若愚 E-mail:chry@cczu.edu.cn
  • 基金资助:

    国家自然科学基金(21101017)资助项目

In situ Synthesis of Cu-SSZ-13/Cordierite Monolithic Catalyst for the Selective Catalytic Reduction of NO with NH3

ZHANG Yu, WANG Hong-Ning, CHEN Ruo-Yu   

  1. School of Petrochemical Engineering, Changzhou University, Changzhou 213164, Jiangsu Province, P. R. China
  • Received:2014-10-09 Revised:2014-12-08 Published:2015-01-26
  • Contact: CHEN Ruo-Yu E-mail:chry@cczu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21101017).

摘要:

采用水热合成技术, 在堇青石蜂窝陶瓷载体上原位合成了SSZ-13分子筛, 并借助X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)等手段对其进行表征. 在此基础上, 研究了合成时间对催化剂结构和机械性能的影响. 另外, 使用固定床反应器测试了离子交换度为50%的Cu-SSZ-13/堇青石催化剂和Cu-SSZ-13催化剂水热老化前后的氨气选择性催化还原(NH3-SCR) NO性能. 结果表明, 通过原位合成法制备的Cu-SSZ-13/堇青石催化剂在200-500 ℃ 的窗口温度内能达到80%以上的转化率, 并在300 ℃ 时达到96.4%的转化率. 在850 ℃水热老化12 h后, Cu-SSZ-13催化剂完全丧失了催化性能, 而Cu-SSZ-13/堇青石催化剂在300 ℃时仍然保持91%的转化率. 使用XRD和固体27Al 核磁共振(27Al NMR)的方法, 研究了水热老化前后两种催化剂结构的变化, 结果表明, 当水热老化12 h 后, Cu-SSZ-13 基本丧失了SSZ-13 结构特征峰, 而Cu-SSZ-13/堇青石仍然保持了一定的SSZ-13 骨架结构. 证明了通过原位合成法制备的Cu-SSZ-13/堇青石催化剂具有较好的抗水热老化性能.

关键词: Cu-SSZ-13分子筛, 水热老化, 原位合成, 堇青石, 氨气选择性催化还原

Abstract:

SSZ-13 molecular sieves were synthesized in situ on the surface of a honeycomb-shaped cordierite support using a hydrothermal method, and the resulting material was characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The process for preparing SSZ-13/cordierite was optimized in detail. Furthermore, the ion exchange levels of the 50% Cu-SSZ-13/cordierite and Cu-SSZ-13 catalysts were tested in the ammonia-selective catalytic reduction (NH3-SCR) of NO both before and after the hydrothermal treatment process using a fixed-bed reactor. The results of these experiments showed that the Cu-SSZ-13/cordierite prepared in situ by hydrothermal synthesis had good catalytic activity, and gave an NO conversion of more than 80% at temperatures in the range of 200-500 ℃, with the highest NO conversion of 96.4%being reached at 300 ℃. After being aged hydrothermally at 850 ℃ for 12 h, the SCR activity of the Cu- SSZ-13 catalyst was significantly reduced, whereas that of Cu-SSZ-13/cordierite remained largely unchanged with an NO conversion of 91% at 300 ℃. Analysis of the catalysts framework both before and after the hydrothermal treatment by X-ray diffraction and solid state 27Al NMR revealed a significant reduction in the intensities of the X-ray diffraction and tetrahedral aluminumpeaks for Cu-SSZ-13, whereas those of the Cu-SSZ- 13/cordierite material remained unchanged. These results indicated that the Cu-SSZ-13/cordierite prepared by in situ hydrothermal synthesis was less prone to deactivation by hydrothermal aging.

Key words: Cu-SSZ-13 molecular sieve, Hydrothermal aging, In situ synthesis, Cordierite, NH3-selective catalytic reduction

MSC2000: 

  • O643