Chinese Journal of Catalysis ›› 2012, Vol. 33 ›› Issue (1): 140-151.DOI: 10.1016/S1872-2067(10)60283-5

• Research papers • Previous Articles     Next Articles

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

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