Zeolite 尾 nanoparticles based bimodal structures: Mechanism and tuning of the porosity and zeolitic properties

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• 作者：Cynthia J. Van Oers ; Mert Kurttepeli ; Myrjam Mertens ; Sara Bals ; Vera Meynen ; Pegie Cool
• 关键词：Nanoparticles ; Zeolite 尾 ; Hierarchical materials ; Electron tomography
• 刊名：Microporous and Mesoporous Materials
• 出版年：1 February, 2014
• 年：2014
• 卷：185
• 期：Complete
• 页码：204-212
• 全文大小：1745 K

文摘

Despite great efforts in the research area of zeolite nanoparticles and their use in the synthesis of bimodal materials, still little is known about the impact of the synthesis conditions of the zeolite nanoparticles on its own characteristics, and on the properties and the formation mechanism of the final bimodal materials. A zeolite 尾 nanoparticles solution is applied in a mesotemplate-free synthesis method, and the influence of the hydrothermal ageing temperature of the nanoparticles solution on both the zeolitic and porosity characteristics of the final bimodal material has been studied. Transmission electron microscopy in combination with 3-dimensional reconstructions obtained by electron tomography revealed that the zeolite 尾 nanoparticles are connected by neck-like structures, thus creating a wormhole-like mesoporous material. Considering the zeolitic properties, a clear threshold is observed in the synthesis temperature series at 413 K. Below and at this threshold, the biporous materials show no apparent zeolitic characteristics, although these materials exhibit a more condensed and uniform Si-O-Si network in comparison to Al-MCF. Synthesis temperatures above the threshold lead to bimodal structures with defined zeolitic properties. Moreover, the dimensions of the nanoparticles are studied by TEM, revealing an increasing particle size with increasing temperature under the threshold of 413 K, which is in agreement with a sol-mechanism. This mechanism is disturbed after the threshold due to the start of the crystallisation process.