Synthesis of ZSM-2 nanocrystals at ambient temperature

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• 作者：Danhua Yuan ; Shutao Xu ; Mozhi Zhang ; Yingxu Wei ; Xinglong Dong ; Yanli He ; Shuliang Xu ; Zhongmin Liu ; Yunpeng Xu
• 关键词：ZSM-2 ; Ambient temperature ; Synthesis ; Crystallization process
• 刊名：Microporous and Mesoporous Materials
• 出版年：1 February, 2014
• 年：2014
• 卷：185
• 期：Complete
• 页码：149-156
• 全文大小：966 K

文摘

ZSM-2 nanorods with crystal size around 50 nm were successfully synthesized at ambient temperature (30 掳C). The crystallization process of ZSM-2 zeolite under ambient temperature was studied and discussed according to the measurement of crystallization kinetic curve, and characterizations with multiple techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), low-temperature N₂ adsorption/desorption analysis, thermogravimetry analysis (TG) and nuclear magnetic resonance (NMR) etc. The ZSM-2 zeolite synthesized at ambient temperature presented different crystal morphologies and large specific area as compared with the sample synthesized at high temperature (100 掳C). Furthermore, ²⁹Si MAS-NMR showed that the nanoscale ZSM-2 obtained by ambient synthesis contained more EMT phase and lower Si/Al ratio than that of micrometer-sized ZSM-2 crystals obtained at 100 掳C. More interestingly, NMR and low-temperature N₂ adsorption/desorption characterizations revealed that the local environment of Al did not change much while that of Si did change a lot during the ambient crystallization process, and the micropore area increased rapidly while the micropore size distributions of the samples changed little with increasing crystallization time.