The Complex Crystal Structure and Abundant Local Defects of Zeolite EMM‐17 Unraveled by Combined Electron Crystallography and Microscopy

Abstract

In this study,w es uccessfully solve polymorphs A and Bo fz eolite EMM-17, whichc an only crystallizei ns ubmicrometer-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 au nique 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 allowu st od irectly observe polymorphs Ba nd Ca nd discover al arge number of local structural defects.Based on structural features unraveled from the reciprocal-space 3D ED data and real-space images,w e propose as eries of energetically feasible local structures in EMM-17. We also demonstrate that the unique porous structure of EMM-17 enables efficient kinetic separation of C 6 alkane isomers.