Molecular Models to Predict the Influence of Templating Molecules on the Structure and Organization of Zeolites

Zeolites are crystalline aluminosilicate materials that are crucial in the modern chemical industry. Their material properties are defined mainly by their framework (FW) connectivity and the local arrangements of heteroatoms like Al or defects. Structure-directing agents (SDAs) are used during synthesis to control zeolite structure. In this dissertation, I used novel techniques to develop computational models and gain insights into the relationships between SDAs and their impact on the crystallization patterns of zeolite. First, I improve the efficacy of the traditional thermodynamic model in predicting the phase selectivity of organic SDAs between full siliceous CHA and AEI. Then, I introduced the Al into zeolite and explored the influence of SDAs on Al distributions in CHA with supercell density functional theory (DFT) models. Finally, I extended the model to further include charged vacancy defects and demonstrated their interaction with SDAs and other Al is indistinguishable from other framework Al. These works will serve as a guide for the industry, enabling the synthesis of zeolites with enhanced catalytic performance at reduced costs.沸石是一类在现代化学工业中具有关键应用价值的结晶铝硅酸盐材料，其材料特性主要由骨架（FW）连接方式以及铝等杂原子或缺陷的局部分布所决定。合成过程中通常使用结构导向剂（SDAs）来调控沸石的晶体结构。本学位论文中，笔者采用新型技术开发计算模型，深入解析了结构导向剂与沸石结晶模式之间的关联及其影响机制。首先，笔者提升了传统热力学模型在预测有机结构导向剂在全硅CHA与AEI型沸石间相选择性方面的效能；随后，将铝原子引入沸石骨架，并借助超胞密度泛函理论（DFT）模型，探究了结构导向剂对CHA型沸石中铝原子分布的调控作用；最后，将模型拓展至包含带电空位缺陷的体系，证实了其与结构导向剂及其他铝原子的相互作用，与骨架内其他铝原子并无二致。本研究成果可为工业界提供重要指导，助力合成兼具更优催化性能与更低制备成本的沸石材料。