催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (1): 140-151.DOI: 10.1016/S1872-2067(10)60283-5

• 研究论文 • 上一篇    下一篇

(NH4)2SiF6 预处理改善 SBA-15 介孔材料的水热稳定性

宋明娟, 邹成龙, 牛国兴*, 赵东元   

  1. 复旦大学化学系, 上海 200433
  • 收稿日期:2011-08-01 修回日期:2011-09-13 出版日期:2012-01-16 发布日期:2015-05-26

Improving the Hydrothermal Stability of Mesoporous Silica SBA-15 by Pre-treatment with (NH4)2SiF6

SONG Mingjuan, ZOU Chenglong, NIU Guoxing*, ZHAO Dongyuan   

  1. Department of Chemistry, Fudan University, Shanghai 200433, China
  • Received:2011-08-01 Revised:2011-09-13 Online:2012-01-16 Published:2015-05-26

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摘要： (NH4)2SiF6 预处理可对 SBA-15 介孔材料的表面缺陷进行补硅修正以及表面疏水化, 从而明显改善 SBA-15 材料的水热稳定性. 结果表明, 用摩尔分数为 5% 的 (NH4)2SiF6 水溶液, 按引入 1% 的 SiO2 计量对 SBA-15 进行处理后, 其水热稳定性明显改善, 在 100 oC 沸水中处理 14 d, 或在 800 oC 下用 100% 水蒸气处理 12 h 后, 均保持较好的介观有序度、形貌及六方孔道结构, 比表面积分别高达 310 和 213 m2/g, 但 (NH4)2SiF6 处理量过高, SBA-15 水热稳定性反而下降.

关键词: 水热稳定性, 氟硅酸铵, SBA-15 分子筛, 介孔材料, 补硅, 疏水化

Abstract: The hydrothermal stability of the mesoporous silica material SBA-15 was improved by a pre-treatment of 5 mol% ammonium hexafluorosilicate solution with 1 mol% SiO2 ratio of (NH4)2SiF6 and SBA-15. The modified SBA-15 kept its ordered meso-structure well even when kept under boiling water for 14 d or 100 % H2O stream at 800 °C for 12 h, and still had BET surface areas as high as 310 and 213 m2/g, respectively, after these treatments. The possible reasons for the stabilization were that the surface defects of SBA-15 were partially repaired by silicon insertion and some silicon hydroxyls were replaced by F- ions. Larger amounts of ammonium hexafluorosilicate did not give more stabilization.

Key words: hydrothermal stability, ammonium fluorosilicate, SBA-15 zeolite, mesoporous material, silicon insertion, hydrophobization