Y沸石纳米晶在碱性环境中的模板组装

摘要

A highly-ordered pure-phase mesoporous material MY was successfully synthesized via the C16H33(CH3)3NBr (CTABr) templated assembly of preformed nano-crystals of zeolite Y under basic conditions. The characterization results showed that different from the conventional mesoporous material MCM-41, Mesoporous Y (MY) contained nano-sized building units of zeolite Y and thus had larger cell parameters and wall thickness; moreover, due to the introduction of nano-crystals of zeolite Y, MY simultaneously owned well-developed microporous and mesoporous structures, which endowed the resulting material with enhance accessibility and led to the lower decomposition temperature of the template. The hydrothermal stability tests revealed that the MY synthesized had much higher stability than MCM-41, giving a crystallinity of 33.5%after being steamed in 100%water vapor for 2 h.%以Y沸石纳米晶为构筑元件，在碱性环境中于表面活性剂十六烷基三甲基溴化铵的模板作用下，合成了一种高度有序的纯相介孔分子筛MY。表征结果表明，MY的孔壁组成不同于常规的MCM-41，前者的晶胞参数及孔壁厚度大于常规MCM-41的，且前者的孔壁厚度达到2.02 nm，为后者的（1.01 nm）2倍，且前者的孔壁中含有Y沸石的纳米晶结构单元。由于Y沸石纳米晶的引入，MY在具有规则介孔的同时也具有较多的微孔结构，这种介-微孔双模孔结构有利于改善活性位的可接近性。Y 沸石纳米晶的引入还使得 MY 的模板剂热分解温度明显低于MCM-41的，使得MY的水热稳定性显著优于MCM-41，经800℃的100%水蒸气处理2 h后，MY仍然能够保留33.5%的介孔结构。