The encapsulation of subnanometric metal entities (isolated metal atoms and metal clusters with a few atoms) in porous materials such as zeolites can be an effective strategy for the stabilization of those metal species and therefore can be further used for a variety of catalytic reactions. However, owing to the complexity of zeolite structures and their low stability under the electron beam, it is challenging to obtain atomic-level structural information of the subnanometric metal species encapsulated in zeolite crystallites. In this protocol, we show the application of a scanning transmission electron microscopy (STEM) technique that records simultaneously the high-angle annular dark-field (HAADF) images and integrated differential phase-contrast (iDPC) images for structural characterization of subnanometric Pt and Sn species within MFI zeolite. The approach relies on the use of a computational model to simulate results obtained under different conditions where the metals are present in different positions within the zeolite. This imaging technique allows to obtain simultaneously the spatial information of heavy elements (Pt and Sn in this work) and the zeolite framework structure, enabling direct determination of the location of the subnanometric metal species. Moreover, we also present the combination of other spectroscopy techniques as complementary tools for the STEM–iDPC imaging technique to obtain global understanding and insights on the spatial distributions of subnanometric metal species in zeolite structure. These structural insights can provide guidelines for the rational design of uniform metal–zeolite materials for catalytic applications.

在诸如沸石的多孔材料中封装亚纳米金属实体（分离的金属原子和具有几个原子的金属簇）可以是稳定这些金属种类的有效策略，因此可以进一步用于各种催化反应。然而，由于沸石结构的复杂性和它们在电子束下的低稳定性，要获得包封在沸石微晶中的亚纳米金属物种的原子级结构信息具有挑战性。在此协议中，我们展示了扫描透射电子显微镜（STEM）技术的应用，该技术可同时记录高角度环形暗场（HAADF）图像和积分微分相衬（iDPC）图像，用于亚纳米级Pt和Pb的结构表征。 MFI沸石中的锡物种。该方法依赖于使用计算模型来模拟在不同条件下获得的结果，其中金属存在于沸石内的不同位置。这种成像技术可以同时获得重元素（本文中的Pt和Sn）和沸石骨架结构的空间信息，从而可以直接确定亚纳米金属种类的位置。此外，我们还介绍了其他光谱技术的组合，作为STEM–iDPC成像技术的补充工具，以获得对沸石结构中亚纳米金属物种的空间分布的整体理解和见识。这些结构见解可为合理设计用于催化应用的均匀金属沸石材料提供指导。