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.

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The real-time observation of structural evolution of materials can provide critical information for understanding their reduction mechanisms under different environments. Herein, we report the atomic-scale observation of the reduction dynamics of WO nanowires (NWs) using environmental transmission electron microscopy. Intriguingly, the reduction pathway is found to be affected by oxygen pressure. Under high oxygen pressure (∼0.095 Pa), a WO NW epitaxially transforms into a WO NW via mass transport across the interface between (010) and (101). While under low oxygen pressure (∼0.0004 Pa), the transformation follows the sequence of WO(NW) → WO(NW) → β-W(nanoparticles), which is identified as a new reduction pathway. These findings reveal the pressure-dependent reduction and a new transformation pathway, and extend our current understanding of the reduction dynamics of metal oxides.