Thermal and hydrothermal stability of framework-substituted MCM-41 mesoporous materials
Thermal and hydrothermal stability of framework-substituted MCM-41 mesoporous materials
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DOI：
10.1016/s0927-6513(97)00079-5
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发表时间：
1997-12-01
期刊：
影响因子：
--
通讯作者：
Chuah, GK
中科院分区：
文献类型：
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作者：
Chen, LY;Jaenicke, S;Chuah, GK
研究了Si/M摩尔比为40（M = Al，Ti）的骨架取代MCM-41的热稳定性和水热稳定性。当在空气中在高达800 ℃的温度下煅烧时，Si被Al或Ti取代2.5%的Si-MCM-41保持介孔。Si-MCM-41和Al-MCM-41的孔结构在高于800 ℃的煅烧温度下塌陷，而Ti-MCM-41的孔塌陷发生在约100 ℃以上。La_2O_3的加入改善了Al-MCM-41在低温下的热稳定性，但在高温下没有影响。当MCM-41材料在25-100 ℃的纯蒸馏水中处理4 h时，Si-MCM-41遭受BET表面积的显著损失，而Al-MCM-41和Ti-MCM-41对这种处理更稳定。研究的所有样品在pH 2的酸性溶液中稳定，但在强碱性介质（pH 12）中迅速崩解。(C)1997年Elsevier Science B.V.
The thermal and hydrothermal stability of framework-substituted MCM-41 with a Si/M molar ratio of 40 (M = Al, Ti) is assessed. Si-MCM-41 with 2.5% substitution of Si by either Al or Ti remains mesoporous when calcined in air at temperatures up to 800 degrees C. The pore structure of Si-MCM-41 and Al-MCM-41 collapses at a calcination temperature of above 800 degrees C, while pore collapse occurs at about 100 degrees C higher for Ti-MCM-41. The addition of La2O3 to Al-MCM-41 improves its thermal stability at lower temperatures, but has no effect at higher temperatures. When MCM-41 materials are treated in pure distilled water at 25-100 degrees C for 4 h, Si-MCM-41 suffers a significant loss of BET surface area, while Al-MCM-41 and Ti-MCM-41 are more stable towards such treatment. All the samples investigated are stable in an acidic solution of pH 2, but disintegrate rapidly in a strongly basic medium (pH 12). (C) 1997 Elsevier Science B.V.