Bores Cecilia, Auerbach Scott M, Monson Peter A
J Phys Chem Lett. 2018 Jul 5;9(13):3703-3707. doi: 10.1021/acs.jpclett.8b01467. Epub 2018 Jun 22.
We investigate the formation of zeolite structures in replica-exchange Monte Carlo simulations of a reactive model of silica polymerization. The simulations incorporate hard spheres to model the effect of excluded volume caused by structure-directing agents (SDAs). We focus on modeling the formation of cage-type zeolite frameworks SOD and LTA. Our model predicts that a relatively wide range of SDA sizes could be used to construct SOD, whereas a narrower range will work for constructing LTA. We also predict that there is potential benefit of including multiple SDAs in each zeolite unit cell, and in the case of LTA with both small and large cavities, there is a strong potential benefit using both small and large SDAs that match the cavities' sizes. We hypothesize that the volume exclusion reduces the configuration space available to the assembling silica units, making it easier for the system to find ordered structures with quasi-spherical cavities.
我们在二氧化硅聚合反应模型的复制交换蒙特卡罗模拟中研究沸石结构的形成。模拟中纳入了硬球，以模拟结构导向剂（SDA）引起的排除体积效应。我们专注于模拟笼型沸石骨架SOD和LTA的形成。我们的模型预测，相对较宽范围的SDA尺寸可用于构建SOD，而构建LTA所需的尺寸范围较窄。我们还预测，在每个沸石晶胞中包含多个SDA可能有益，对于同时具有小腔和大腔的LTA，使用与腔尺寸匹配的小SDA和大SDA有很大的潜在益处。我们推测体积排除减少了组装二氧化硅单元可用的构型空间，使系统更容易找到具有准球形腔的有序结构。
