title: Unravelling surface and interfacial structures of a metal-organic framework by transmission electron microscopy.
abstract: Metal-organic frameworks (MOFs) are crystalline porous materials with designable topology, porosity and functionality, having promising applications in gas storage and separation, ion conduction and catalysis. It is challenging to observe MOFs with transmission electron microscopy (TEM) due to the extreme instability of MOFs upon electron beam irradiation. Here, we use a direct-detection electron-counting camera to acquire TEM images of the MOF ZIF-8 with an ultralow dose of 4.1 electrons per square ångström to retain the structural integrity. The obtained image involves structural information transferred up to 2.1 Å, allowing the resolution of individual atomic columns of Zn and organic linkers in the framework. Furthermore, TEM reveals important local structural features of ZIF-8 crystals that cannot be identified by diffraction techniques, including armchair-type surface terminations and coherent interfaces between assembled crystals. These observations allow us to understand how ZIF-8 crystals self-assemble and the subsequent influence of interfacial cavities on mass transport of guest molecules.
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Yihan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Jim
authors.initials: J
authors.lastname: Ciston
authors.affiliation: School of Materials Science and Engineering, Xi'an University of Science and Technology, Xi'an 710054, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Imaging and Characterization Core Lab, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Miao
authors.affiliation: Gatan, Inc., Pleasanton, California 94588, USA.
authors.forename: Cory
authors.initials: C
authors.lastname: Czarnik
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Yichang
authors.initials: Y
authors.lastname: Pan
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Imaging and Characterization Core Lab, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Rachid
authors.initials: R
authors.lastname: Sougrat
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Zhiping
authors.identifier: 0000-0001-9555-6009
authors.initials: Z
authors.lastname: Lai
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Chia-En
authors.initials: CE
authors.lastname: Hsiung
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Kexin
authors.initials: K
authors.lastname: Yao
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Ingo
authors.initials: I
authors.lastname: Pinnau
authors.affiliation: Gatan, Inc., Pleasanton, California 94588, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Pan
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Yu
authors.identifier: 0000-0003-1462-1118
authors.initials: Y
authors.lastname: Han