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In this study, we successfully solve polymorphs A and B of zeolite EMM‐17, which can only crystallize in sub‐micrometer‐sized crystals while containing complex stacking disorders, from the three‐dimensional (3D) electron diffraction (ED) data. This is the first time that the atomic structure of this polymorph has been ab initio solved, and the result reveals a unique 10(12)×10(12)×11‐ring channel system. Moreover, we acquire the first atomic‐resolution images of EMM‐17 using integrated differential phase‐contrast scanning transmission electron microscopy. The images allow us to directly observe polymorphs B and C and discover a large number of local structural defects. Based on structural features unraveled from the reciprocal‐space 3D ED data and real‐space images, we propose a series of energetically feasible local structures in EMM‐17. We also demonstrate that the unique porous structure of EMM‐17 enables efficient kinetic separation of C6 alkane isomers. [ABSTRACT FROM AUTHOR]

Integrated differential phase‐contrast scanning transmission electron microscopy (iDPC‐STEM) is capable of directly probing guest molecules in zeolites, owing to its sufficient and interpretable image contrast for both heavy and light elements under low‐dose conditions. This unique ability is demonstrated by imaging volatile organic compounds adsorbed in zeolite Silicalite‐1; iDPC‐STEM was then used to investigate molybdenum supported on various zeolites including Silicalite‐1, ZSM‐5, and mordenite. Isolated single‐Mo clusters were observed in the micropores of ZSM‐5, demonstrating the crucial role of framework Al in driving Mo atomically dispersed into the micropores. Importantly, the specific one‐to‐one Mo‐Al interaction makes it possible to locate Al atoms, that is, catalytic active sites, in the ZSM‐5 framework from the images, according to the positions of Mo atoms in the micropores. [ABSTRACT FROM AUTHOR]

Tailoring the morphology of a specific crystalline material through distinct crystal growth mechanisms (classical and nonclassical) is challenging. Herein, we report the two unique morphologies of a medium‐pore (10×8‐ring) zeolite, ZSM‐57, prepared by employing an identical organic structure‐directing agent (OSDA) and different inorganic cations, namely Na+ and K+, denoted as ZSM‐57‐Na (pentagonal nanoplates) and ZSM‐57‐K (pentagonal nanoprisms), respectively. The tunable twin domain size and twin boundaries in both samples have been unraveled at the atomic level by electron crystallography. It is of significance to note that the 10‐ring pore openings run perpendicular to the pentagonal nanoplates and nanoprisms. Moreover, the distinct crystal growth mechanisms, which result in the different unique morphologies and tunable twin domains, were further determined by electron crystallography combined with other techniques. Nonclassical growth involving the aggregation of amorphous aluminosilicate nanoparticles to the smooth ZSM‐57‐Na crystal surface dominates the ZSM‐57‐Na crystallization process. For the ZSM‐57‐K sample, the classical layer‐by‐layer growth through the addition of silica molecules to advancing steps on the crystal surface dominates the ZSM‐57‐K crystallization process. The different morphologies of both samples result in the distinct catalytic lifespan of the methanol conversion and selectivity of lower olefins. Bridging the gap: Tunable nonclassical and classical crystal growth mechanisms in the ZSM‐57 zeolite have been revealed with the aid of electron crystallography (see figure). The different mechanisms lead to zeolites with different unique morphologies and twin domains than can be tuned by varying the metal cation in the reaction medium. The methanol conversion reaction revealed the two zeolites with different morphologies exhibit different catalytic behavior. [ABSTRACT FROM AUTHOR]

The structure solution, prediction, and targeted synthesis of a family of embedded isoreticular zeolites (EIZs) with expanding structural complexity, denoted the RHO family, were reported recently. Here, the naming and building rules of body-centered cubic EIZs with the lta cage as the lattice point are presented. The rearrangement of a pair of pau and d8r cages between two lta cages and its repetitive insertion, combined with the strong reflections and fragment methods, allows the creation of three other new zeolite families, designated the HPO, RHO(b), and KFI families. Among them, the KFI family is found to be the only EIZ family, on the basis of the similarity of structure factor amplitudes and phases of strong reflections, that is, structural coding, within its family members. The structural credibility of this family is confirmed by both local interatomic distances and T−T−T angle analyses. The existence of tetragonal EIZ families is also demonstrated. The overall results provide useful insights into the prediction of unprecedented EIZ families. [ABSTRACT FROM AUTHOR]

A novel structural coding approach combining structure solution, prediction, and the targeted synthesis of new zeolites with expanding complexity and embedded isoreticular structures was recently proposed. Using this approach, the structures of two new zeolites in the RHO family, PST-20 and PST-25, were predicted and synthesized. Herein, by extending this approach, the next two higher generation members of this family, PST-26 and PST-28, have been predicted and synthesized. These two zeolites have much larger unit cell volumes (422 655 Å3 and 614 912 Å3, respectively) than those of the lower generations. Their crystallization was confirmed by a combination of both powder X-ray and electron diffraction techniques. Aluminate and water concentrations in the synthetic mixture were found to be the two most critical factors influencing the structural expansion of embedded isoreticular zeolites under the synthetic conditions studied herein. [ABSTRACT FROM AUTHOR]

The naming and building rules of body‐centered cubic embedded isoreticular zeolites (EIZs) with lta cage as the lattice point are presented. The procedures for the classification, description, and prediction presented herein will serve as a guideline for finding new EIZs and, eventually, for zeolites and related microporous materials with desired properties. More information can be found in the Full Paper by X. Zou, S. B. Hong et al. on page 15922. [ABSTRACT FROM AUTHOR]