(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℃沸水中处理14d,或在800℃下用100％水蒸气处理12h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.%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 ℃ 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.
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