摘要
以合成的微孔分子筛MCM-22为原料，将其与表面活性剂及氢氧化钠-起回流溶解，再调节溶液的pH值至7～9，使MCM-22转化为高水热稳定性的介孔材料．所得介孔材料具有蠕虫状的均匀孔道，骨架中不含有MCM．22的微观结构单元．该介孔材料至少含有18％的表面活性剂，经823K焙烧脱除表面活性剂后，其孔径为2．2nm，比表面积为1038m2／g，孔容为0．97cm3／g．焙烧后的介孔材料具有非常高的水热稳定性，经沸水回流100h后其比表面积为896m2／g，孔容为0．90cm3／g，孔径为2．1nm，即使经过300h的回流，该材料仍能保持698m。／g的比表面积和0．90cm3／g的孔容．固体29SiMASNMR结果表明，该介孔材料的高水热稳定性与其高表面缩合度有关．
A microporous zeolite MCM-22 was synthesized and transferred to mesoporous materials with high hydrothermal stability by refluxing MCM-22 with surfactant in the presence of NaOH followed by adjusting the pH to 7-9. The obtained material exhibited uniform wormhole mesopores while had no primary structural units of MCM-22 in the mesoporous framework. The as-synthesized mesoporous material contained at least 18 % surfactant, which can be removed by calcination at 823 K. The calcined mesoporous material had a pore diameter of 2.2 nm, a BET specific surface area of 1 038 m2/g, and a pore volume of 0.97 cm3/g. The calcined mesoporous materials exhibited excellent hydrothermal stability. After being refluxed in boiling water for 100 h, the material remained a BET specific surface area of 896 m2/g, a high pore volume of 0.90 cm3/g, and a pore diameter of 2.1 nm. Even after refluxing for 300 h, a high BET specific surface area of 698 m2/g and a high pore volume of 0.90 cm3/g could still be obtained. The remarkable hydrothermal stability of this mesoporous material was due to its highly polymerized pore walls ascribed by solid-state 29Si MAS NMR.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2008年第9期928-934,共7页
基金
中国博士后科学基金面上资助项目.
关键词
MCM-22
介孔材料
水热稳定性
后处理
MCM-22
mesoporous material
hydrothermal stability
post-synthetic treatment
