Iyoki Kenta, Kikumasa Kakeru, Onishi Takako, Yonezawa Yasuo, Chokkalingam Anand, Yanaba Yutaka, Matsumoto Taiji, Osuga Ryota, Elangovan Shanmugam P, Kondo Junko N, Endo Akira, Okubo Tatsuya, Wakihara Toru
Department of Chemical System Engineering , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656 , Japan.
Institute of Industrial Science , The University of Tokyo , 4-6-1 Komaba, Meguro-ku , Tokyo 153-8505 , Japan.
J Am Chem Soc. 2020 Feb 26;142(8):3931-3938. doi: 10.1021/jacs.9b12709. Epub 2020 Feb 14.
Improving the stability of porous materials for practical applications is highly challenging. Aluminosilicate zeolites are utilized for adsorptive and catalytic applications, wherein they are sometimes exposed to high-temperature steaming conditions (∼1000 °C). As the degradation of high-silica zeolites originates from the defect sites in their frameworks, feasible defect-healing methods are highly demanded. Herein, we propose a method for healing defects to create extremely stable high-silica zeolites. High-silica (SiO/AlO > 240) zeolites with *BEA-, MFI-, and MOR-type topologies could be stabilized by significantly reducing the number of defect sites via a liquid-mediated treatment without using additional silylating agents. Upon exposure to extremely high temperature (900-1150 °C) steam, the stabilized zeolites retain their crystallinity and micropore volume, whereas the parent commercial zeolites degrade completely. The proposed self-defect-healing method provides new insights into the migration of species through porous bodies and significantly advances the practical applicability of zeolites in severe environments.
提高多孔材料在实际应用中的稳定性极具挑战性。铝硅酸盐沸石用于吸附和催化应用，有时会暴露在高温蒸汽条件下（约1000°C）。由于高硅沸石的降解源于其骨架中的缺陷位点，因此迫切需要可行的缺陷修复方法。在此，我们提出了一种修复缺陷以制备极其稳定的高硅沸石的方法。具有BEA、MFI和MOR拓扑结构的高硅（SiO/AlO>240）沸石可以通过液体介导的处理显著减少缺陷位点的数量而无需使用额外的硅烷化剂来实现稳定化。在暴露于极高温度（900-1150°C）的蒸汽中时，稳定化的沸石保留其结晶度和微孔体积，而母体商业沸石则完全降解。所提出的自缺陷修复方法为物质在多孔体中的迁移提供了新的见解，并显著提高了沸石在恶劣环境中的实际适用性。
