A Germanosilicate Structure with 11×11×12‐Ring Channels Solved by Electron Crystallography

Abstract

Zeolites have been widely used in industry owing to their ordered micropores and stable frameworks. The pore sizes and shapes are the key parameters that affect the selectivity and efficiency in their applications in catalysis, sorption, and separation. Zeolites with pores defined by 10 and 12 TO4 tetrahedra are often used for various catalytic processes. To optimize the performance of zeolites, it is extremely desirable to fine-tune the pore sizes/shapes. The first germanosilicate zeolite with a three-dimensional 11×11×12-ring channel system, PKU-16 (PKU, Peking University) is presented. Nanosized PKU-16 was structurally characterized by the new three-dimensional rotation electron diffraction (RED) technique. PKU-16 is structurally related to the zeolite β polymorph C (BEC, 12×12×12-ring channels) by rotating half of the four-rings in double mtw units.

Isostructural Three‐Dimensional Covalent Organic Frameworks

“…[12a] Alternatively,well-crystalline powder samples can be synthesized, and atomic resolution can then hopefully be reached with powder X-ray diffraction (PXRD) or 3D electron diffraction (ED) techniques. By using continuous rotation electron diffraction (cRED) techniques, [15] the resolution of these 3D ED datasets reached up to 0.9-1.0 ,revealing the location of all non-hydrogen atoms directly from ap olycrystalline COF sample for the first time.A ll three isostructural 3D COFs adopt afivefold interpenetrated pts topology,and because of the precise control of the pore environments,these 3D COFs exhibit different gas absorption behaviors,such as selectivity for CO 2 over N 2 .T he 3D COF with C À Fb onds on the pore surface showed the highest selectivity. [9d, 10c, 12b] Herein, we describe the design and synthesis of three isostructural 3D COFs (Figure 1), in which the pore environment has been finely tuned without changing the topology and interpenetration degree.B ys electively choosing the precursors and connection patterns,t hree isostructural 3D COFs functionalized with -H, -Me,a nd -F substituents have been synthesized.…”

Interrupted Chalcogenide‐Based Zeolite‐Analogue Semiconductor: Atomically Precise Doping for Tunable Electro‐/Photoelectrochemical Properties

“…[1] Enormous economic benefits brought by these porous materials have stimulated long-lasting academic research interest in exploration of zeolite materials with variable composition and new types of frameworks. [3] However, the inherent insulating characteristic of oxide-based zeolites greatly limits their applications in the aspect of photo-/electric-related processes. [3] However, the inherent insulating characteristic of oxide-based zeolites greatly limits their applications in the aspect of photo-/electric-related processes.…”

“…[3] However, the inherent insulating characteristic of oxide-based zeolites greatly limits their applications in the aspect of photo-/electric-related processes. [2,4] In fact, three other metal chalcogenides with zeolitic framework reported in Ref. [4] Such methodology is proved to have successfully integrated both zeolitic architecture and semiconductor properties into one material which possesses both high specific surface area and UV/Vis photocatalytic activity.…”

“…Even though there are only six cases with the framework exclusively formed by 3-MR in the zeolite framework database, [2] no one is associated with an interrupted structure. Even though there are only six cases with the framework exclusively formed by 3-MR in the zeolite framework database, [2] no one is associated with an interrupted structure.…”

“…Even though there are only six cases with the framework exclusively formed by 3-MR in the zeolite framework database, [2] no one is associated with an interrupted structure. Although CSZ-5-InSe is bestowed with a zeolitic framework due to tetrahedrally coordinated metal sites, the interrupted structure leads to a previously unknown (3,4)-connected net with vertex symbols (3.12.3.12.3. [9] Interestingly, integration of the interrupted framework with the exclusive primary building unit 3-MR makes such a net bearing quite low framework density.…”