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.

沸石是一类至关重要的晶态铝硅酸盐材料，在现代化学工业中占据核心地位。其材料属性主要取决于其框架（FW）连接性和局部异原子如铝或缺陷的排列。在合成过程中，结构导向剂（SDAs）被用于调控沸石结构。在本篇论文中，我运用新颖的技术开发计算模型，并深入探讨了结构导向剂与沸石结晶模式之间的影响关系。首先，我提升了传统热力学模型在预测有机结构导向剂在完全硅质CHA与AEI之间的相选择性方面的效能。随后，我将铝引入沸石中，并利用超胞密度泛函理论（DFT）模型探讨了结构导向剂对CHA中铝分布的影响。最后，我扩展了模型，进一步纳入带电空位缺陷，并展示了其与结构导向剂及其他铝同素异形体的相互作用。这些研究成果将为工业界提供指导，有助于在降低成本的同时合成具有卓越催化性能的沸石。