Institute of New Catalytic Materials Science, Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071, China.
Langmuir. 2012 Jun 12;28(23):8600-7. doi: 10.1021/la300447n. Epub 2012 May 31.
Mesoporous zeolite silicalite-1 and Al-ZSM-5 with intracrystalline mesopores were synthesized with polyelectrolyte-surfactant complex as the template. Complex colloids were first formed by self-assembly of the anionic polymer poly(acrylic acid) (PAA) and the cationic surfactant cetyltrimethylammonium bromide (CTAB) in basic solution. During the synthesis procedure, upon the addition of the silica source, microporous template (tetrapropylammonium hydroxide), and NaCl, these PAA/CTA complex colloids underwent dissociation and gave rise to the formation of hollow silica spheres with mesoporous shells templated by CTAB micelles and PAA domains as the core. Under hydrothermal treatment, the hollow silica spheres gradually merged together to form larger particles with the PAA domains embedded as the space occupant, which acted as a template for intracrystalline mesopores during the crystallization of the zeolite framework. Amphiphilic organosilane was used to enhance the connection between the PAA domain and the silica phase during the synthesis. After calcination, single crystal-like zeolite particles with intracrystalline mesopores of about 5-20 nm were obtained, as characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N(2) adsorption measurements. With the addition of an aluminum source in the synthesis, mesoporous zeolite Al-ZSM-5 with intracrystalline mesopores was also synthesized, and enhanced catalytic property was observed with mesoporous Al-ZSM-5 in acetalization of cyclohexanone with methanol.
介孔硅沸石-1 和 Al-ZSM-5 具有晶内介孔，是通过使用聚电解质-表面活性剂复合物作为模板合成的。在碱性溶液中，通过阴离子聚合物聚丙烯酸（PAA）和阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）的自组装首先形成了复合胶体。在合成过程中，加入硅源、微孔模板（四丙基氢氧化铵）和 NaCl 后，这些 PAA/CTA 复合胶体发生解离，并形成具有介孔壳的中空硅球，介孔壳由 CTAB 胶束和 PAA 域模板。在水热处理下，中空硅球逐渐融合在一起，形成具有 PAA 域嵌入作为空间占位符的较大颗粒，在沸石骨架结晶过程中，PAA 域充当晶内介孔的模板。两亲性有机硅烷在合成过程中用于增强 PAA 域和硅相之间的连接。煅烧后，得到具有约 5-20nm 晶内介孔的单晶状沸石颗粒，通过 X 射线衍射、扫描电子显微镜、透射电子显微镜和 N2 吸附测量进行了表征。在合成中加入铝源，还合成了具有晶内介孔的介孔沸石 Al-ZSM-5，并在环己酮与甲醇的缩醛化反应中观察到介孔 Al-ZSM-5 具有增强的催化性能。
