Wang Zijian, Ke Ming, Song Zhaozheng
College of Science, China University of Petroleum Beijing 102249 China
RSC Adv. 2025 Mar 20;15(11):8696-8706. doi: 10.1039/d5ra00666j. eCollection 2025 Mar 17.
Mordenite is extensively utilized in the domains of adsorption and catalysis owing to its excellent selectivity, stability, and renewability. In this work, the effects of crystal seeds, the ratio of SiO/AlO, crystallization temperature, silicon source, and structure directing agents on the morphologies of mordenite are investigated by utilizing hexamethyleneimine (HMI) as the OSDA. Results indicate that the transformation of rod-like and flake-like mordenites is mainly related to the increasing ratio of SiO/AlO, and the formation of flake-like morphology is related to various conditions. On a macro level, the rod-like and flake-like zeolites are formed by transforming amorphous precursors into small crystals and growing them epitaxially. On a micro level, HMIH progressively displaces Na to balance the framework charge with the increasing ratio of SiO/AlO. DFT calculation and nuclear magnetic resonance results confirm the specific guidance of HMI on the T and T sites of the rod-like and flake-like mordenites. The conclusion can serve as a reference for regulating the morphology and active sites of mordenite.
丝光沸石因其优异的选择性、稳定性和可再生性而在吸附和催化领域得到广泛应用。在本工作中，以六亚甲基亚胺（HMI）作为有机结构导向剂，研究了晶种、SiO/AlO比、晶化温度、硅源和结构导向剂对丝光沸石形貌的影响。结果表明，棒状和片状丝光沸石的转变主要与SiO/AlO比的增加有关，片状形貌的形成与多种条件有关。在宏观层面上，棒状和片状沸石是通过将无定形前驱体转变为小晶体并使其外延生长而形成的。在微观层面上，随着SiO/AlO比的增加，HMIH逐渐取代Na以平衡骨架电荷。密度泛函理论计算和核磁共振结果证实了HMI对棒状和片状丝光沸石的T和T位点的特定导向作用。该结论可为调控丝光沸石的形貌和活性位点提供参考。
