高等学校化学学报 ›› 2023, Vol. 44 ›› Issue (10): 20230034.doi: 10.7503/cjcu20230034

• 研究论文: 无机化学 • 上一篇    下一篇

L沸石晶间转化快速合成SSZ-13沸石及其中空结构形成机理

张宗洋, 李玉平(), 张若茜, 刘宇峰, 陈泽, 韩丽娜, 韩培德   

  1. 太原理工大学材料科学与工程学院, 太原 030024
  • 收稿日期:2023-01-31 出版日期:2023-10-10 发布日期:2023-04-07
  • 通讯作者: 李玉平 E-mail:liyuping@tyut.edu.cn
  • 基金资助:
    国家自然科学基金(21978195);山西省应用基础研究项目(201701D121024)

Rapid Synthesis of SSZ-13 Zeolite via Interzeolite Transformation of L Zeolite and Formation Mechanism of Its Hollow Structure

ZHANG Zongyang, LI Yuping(), ZHANG Ruoxi, LIU Yufeng, CHEN Ze, HAN Lina, HAN Peide   

  1. College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China
  • Received:2023-01-31 Online:2023-10-10 Published:2023-04-07
  • Contact: LI Yuping E-mail:liyuping@tyut.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21978195);the Natural Science Foundation of Shanxi Province, China(201701D121024)

摘要:

N,N,N-三甲基-1-金刚烷胺氢氧化物(TMAdaOH)为有机模板, 在180 ℃晶化温度下, 通过补加硅源, 以低硅铝比L沸石直接转晶合成SSZ-13分子筛. 采用XRD, FTIR, SEM, N2吸附-脱附和HRTEM等表征手段对晶化过程进行了跟踪, 发现180 ℃高温下晶化4.5 h即可获得高结晶度的SSZ-13沸石; 且在该实验条件下, 晶化过程中晶粒出现了中空现象. 进一步结合SEM-EDS表征结果对中空现象的形成机理进行了研究, 发现主要是由于在低硅L沸石缓慢降解和SSZ-13快速成核和生长过程中, 存在晶粒中间部位较边缘硅铝比高的现象, 即晶粒硅铝比分布不均匀. 随着晶化时间的延长, 富硅的晶核会在碱液作用下选择性脱硅, 从而产生中空现象. 最后对合成的中空样品进行铜离子交换, 测试其对NO x 的NH3选择性催化还原反应的催化性能, 并结合NH3程序升温脱附(NH3-TPD)和H2程序升温还原(H2-TPR)表征对催化结果进行了分析.

关键词: SSZ-13沸石, 晶间转化, L沸石, 中空沸石, NH3选择性催化还原(NH3-SCR)反应

Abstract:

Using NNN-trimethyl-1-amantamine hydroxide(TMAdaOH) as organic structure directing agents, SSZ-13 zeolite was synthesized by direct conversion of zeolite L with a low SiO2/Al2O3 ratio(SAR) by adding additional Si source at 180 ℃. The crystallization process was tracked by XRD, FTIR, SEM, N2 adsorption-desorption and HRTEM characterization. It was found that the crystallization rate was greatly accelerated at 180 ℃, and highly crystalline SSZ-13 was synthesized after 4.5 h of crystallization. At the same time, it was noted that hollow crystals appeared during the crystallization process under this experimental condition. The formation mechanism of the hollowing structure was further explored by combining with SEM-EDS characterization. It was found that during the process of slow degradation of zeolite L and the simultaneous rapid nucleation and growth of SSZ-13, the SAR in the middle of zeolite crystals was higher than that at the edge, that is, the SAR distribution in the whole crystal was uneven. Silicon-rich crystal nucleus can be selectively desilicated under alkaline conditions, leading to the hollow phenomenon. Finally, the catalytic performance of the hollow samples after copper ion exchange in NH3 selective catalytic reduction(NH3-SCR) reaction of NO x was investigated, and the catalytic results were analyzed in combination with the characterization of NH3 temperature-programmed desorption(NH3-TPD) and H2 temperature-programmed reduction(H2-TPR).

Key words: SSZ-13 zeolite, Interzeolite transformation, L zeolite, Hollow zeolite, NH3 selective catalytic reduction(NH3-SCR) reaction

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