Formation of zeolite supported Ag⁰ clusters depends on a combination of thermodynamically stable atomic configurations, charge balance considerations, and mobility of species on the surface and within pores. Periodic density functional theory (DFT) calculations were performed to evaluate how the location of Al in the mordenite (MOR) framework and humidity control Ag⁰ nanocluster formation. Four Al framework sites were studied (T1-T4) and the Al positions in the framework were identified by the shifts in the differential Al⋯Al pair distribution function (PDF). Furthermore, structural information about the Ag⁰ nanoclusters, such as dangling bonds, can be identified by Ag⋯Ag PDF data. For Ag⁰ formation in vacuum MOR structures with a Si:Al ratio of 5:1 with Al in the T1 position resulted in the most framework flexibility and the lowest Ag⁰ nanocluster charge, indicating the best result for formation of charge neutral nanoclusters. When water is present, Al in the T3 and T4 positions results in the formation of the smallest average Ag⁰ nanoclusters plus greater expansion of the O-T-O bond angle than in vacuum, indicating easier diffusion of the Ag⁰ nanoclusters to the surface. The presence of Al in 4-membered rings and in pairs indicates favorable MOR structures for formation of single Ag atoms, despite the existence of synthesis challenges. Therefore, Al in the T2 position is the least favorable for Ag⁰ nanocluster formation in both vacuum and in the presence of water. Al in the T1, T3, and T4 positions provides beneficial effects through framework flexibility and changes in nanocluster size or charge that can be leveraged for design of zeolites for formation of metallic nanoclusters.

沸石负载的 Ag ⁰簇的形成取决于热力学稳定的原子构型、电荷平衡考虑以及表面和孔内物质的流动性的组合。进行周期性密度泛函理论 (DFT) 计算以评估 Al 在丝光沸石 (MOR) 框架中的位置和湿度控制 Ag ⁰纳米团簇的形成。研究了四个 Al 骨架位点 (T1-T4)，并通过差分 Al⋯Al 对分布函数 (PDF) 的变化确定了骨架中的 Al 位置。此外，Ag ⁰纳米团簇的结构信息，例如悬空键，可以通过 Ag⋯Ag PDF 数据识别。对于银⁰在真空 MOR 结构中形成的 Si:Al 比为 5:1，Al 在 T1 位置导致最大的骨架柔韧性和最低的 Ag ⁰纳米团簇电荷，表明形成电荷中性纳米团簇的最佳结果。当存在水时，T3 和 T4 位置的 Al 导致形成最小的平均 Ag ⁰纳米团簇以及比真空中更大的 OTO 键角扩展，表明 Ag ⁰纳米团簇更容易扩散到表面。尽管存在合成挑战，但 Al 在 4 元环中和成对存在表明形成单个 Ag 原子的有利 MOR 结构。因此，T2位置的Al对Ag ⁰最不利在真空和存在水的情况下形成纳米团簇。T1、T3 和 T4 位置的铝通过框架灵活性和纳米团簇尺寸或电荷的变化提供有益效果，这些变化可用于设计沸石以形成金属纳米团簇。