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  • 1. Aramburo, Luis R.
    et al.
    Karwacki, Lukasz
    Cubillas, Pablo
    Asahina, Shunsuke
    de Winter, D. A. Matthijs
    Drury, Martyn R.
    Buurmans, Inge L. C.
    Stavitski, Eli
    Mores, Davide
    Daturi, Marco
    Bazin, Philippe
    Dumas, Paul
    Thibault-Starzyk, Frederic
    Post, Jan A.
    Anderson, Michael W.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Weckhuysen, Bert M.
    The Porosity, Acidity, and Reactivity of Dealuminated Zeolite ZSM-5 at the Single Particle Level: The Influence of the Zeolite Architecture2011In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 49, p. 13773-13781Article in journal (Refereed)
    Abstract [en]

    A combination of atomic force microscopy (AFM), high-resolution scanning electron microscopy (HR-SEM), focused-ion-beam scanning electron microscopy (FIB-SEM), X-ray photoelectron spectroscopy (XPS), confocal fluorescence microscopy (CFM), and UV/Vis and synchrotron-based IR microspectroscopy was used to investigate the dealumination processes of zeolite ZSM-5 at the individual crystal level. It was shown that steaming has a significant impact on the porosity, acidity, and reactivity of the zeolite materials. The catalytic performance, tested by the styrene oligomerization and methanol-to-olefin reactions, led to the conclusion that mild steaming conditions resulted in greatly enhanced acidity and reactivity of dealuminated zeolite ZSM-5. Interestingly, only residual surface mesoporosity was generated in the mildly steamed ZSM-5 zeolite, leading to rapid crystal coloration and coking upon catalytic testing and indicating an enhanced deactivation of the zeolites. In contrast, harsh steaming conditions generated 550 nm mesopores, extensively improving the accessibility of the zeolites. However, severe dealumination decreased the strength of the Bronsted acid sites, causing a depletion of the overall acidity, which resulted in a major drop in catalytic activity.

  • 2. Arcos, D.
    et al.
    Lopez-Noriega, A.
    Ruiz-Hernandez, E.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Vallet-Reg, M.
    Ordered Mesoporous Microspheres for Bone Grafting and Drug Delivery2009In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 21, no 6, p. 1000-1009Article in journal (Refereed)
    Abstract [en]

    Bioactive microspheres with ordered mesoporous structure have been synthesized by means of the evaporation-induced self-assembly (EISA) method and following an aerosol-assisted route. The bioactive microspheres belong to the SiO2-CaO-P2O5 systems, and the mesoporous structure closely depends on the structure-directing agent as well as its interaction with the Ca2+ cations during the mesophase formation. Among the different tested surfactants, the triblock copolymer F127 leads to hexagonal ordered structures for low CaO contents, P123 leads to wormlike mesoporous structures for any CaO content, whereas the ionic surfactant cetyltrimethyl ammonium bromide (C16TAB) does not produce accessible mesopores at the external surface, for any CaO content. All the mesoporous SiO2-CaO-P2O5 microspheres develop an apatite like layer when reacting with simulated body fluid. Preliminary tests indicate the capability to load and release triclosan with kinetic profiles that depend on the pore structure, thus showing interesting features to be used in periodontal regenerative surgery and infection profilaxis.

     

  • 3. Asahina, Shunsuke
    et al.
    Suga, Mitsuo
    Takahashi, Hideyuki
    Jeong, Hu Young
    Galeano, Carolina
    Schueth, Ferdi
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Korea Advanced Institute of Science & Technology (KAIST), South Korea.
    Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer2014In: APL materials, ISSN 2166-532X, Vol. 2, no 11, p. 113317-Article in journal (Refereed)
    Abstract [en]

    Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in york-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the york-shell materials: (i) resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii) sample preparation for observing internal structures; and (iii) X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

  • 4. Asahina, Shunsuke
    et al.
    Takami, Seiichi
    Otsuka, Takeshi
    Adschiri, Tadafumi
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Exploitation of Surface-Sensitive Electrons in Scanning Electron Microscopy Reveals the Formation Mechanism of New Cubic and Truncated Octahedral CeO(2) Nanoparticles2011In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 3, no 6, p. 1038-1044Article in journal (Refereed)
    Abstract [en]

    Development of new analytical tools for nanostructures directly contributes to the study of catalysts. By using scanning electron microscopy (SEM) with a newly designed signal enhancer, we study cubic and truncated octahedral cerium oxide (CeO(2)) nanoparticles, which are composed of smaller primary octahedral CeO(2) and are formed through bond formation with hexanedioic acid. The signal enhancer is designed to efficiently collect secondary electrons of kinetic energy less than 10 eV; thus, it greatly improves the S/N ratio. On the basis of the observed SEM images and electron backscattered diffraction patterns of the cross section of the nanoparticles, we discuss the formation mechanism of the nanoparticles and speculate that the primary CeO(2) nanocrystals share their edges in the cubic nanoparticles and truncated octahedral nanoparticles. These results will contribute to the preparation of nanostructured metal oxide surfaces with controlled morphologies that could enhance catalytic activity.

  • 5. Asahina, Shunsuke
    et al.
    Uno, Shinobu
    Suga, Mitsuo
    Stevens, Sam
    Klingstedt, Miia
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Okano, Yasuyuki
    Kudo, Masato
    Schuth, Ferdi
    Anderson, Michael
    Adschiri, Tadafumi
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    A new HRSEM approach to observe fine structures of novel nanostructured materials2011In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 146, no 1-3, p. 11-17Article in journal (Refereed)
    Abstract [en]

    A new approach for observing fine structures of novel thin, nanostructured materials called through the employed to observe interesting features on a variety of new, catalyticallyimportant hierarchically porous rattlespheres.

  • 6. Brand, Stephen K.
    et al.
    Schmidt, Joel E.
    Deem, Michael W.
    Daeyaert, Frits
    Ma, Yanhang
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). ShanghaiTech University, China.
    Orazov, Marat
    Davis, Mark E.
    Enantiomerically enriched, polycrystalline molecular sieves2017In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, no 20, p. 5101-5106Article in journal (Refereed)
    Abstract [en]

    Zeolite and zeolite-like molecular sieves are being used in a large number of applications such as adsorption and catalysis. Achievement of the long-standing goal of creating a chiral, polycrystalline molecular sieve with bulk enantioenrichment would enable these materials to perform enantioselective functions. Here, we report the synthesis of enantiomerically enriched samples of a molecular sieve. Enantiopure organic structure directing agents are designed with the assistance of computational methods and used to synthesize enantioenriched, polycrystalline molecular sieve samples of either enantiomer. Computational results correctly predicted which enantiomer is obtained, and enantiomeric enrichment is proven by high-resolution transmission electron microscopy. The enantioenriched and racemic samples of the molecular sieves are tested as adsorbents and heterogeneous catalysts. The enantioenriched molecular sieves show enantioselectivity for the ring opening reaction of epoxides and enantioselective adsorption of 2-butanol (the R enantiomer of the molecular sieve shows opposite and approximately equal enantioselectivity compared with the S enantiomer of the molecular sieve, whereas the racemic sample of the molecular sieve shows no enantioselectivity).

  • 7. Brent, Rhea
    et al.
    Cubillas, Pablo
    Stevens, Sam M.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Jelfs, Kim E.
    Umemura, Ayako
    Gebbie, James T.
    Slater, Ben
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Holden, Mark A.
    Anderson, Michael W.
    Unstitching the Nanoscopic Mystery of Zeolite Crystal Formation2010In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 39, p. 13858-13868Article in journal (Refereed)
    Abstract [en]

    A molecular-scale understanding of crystal growth is critical to the development of important materials such as pharmaceuticals, semiconductors and catalysts. Only recently has this been possible with the advent of atomic force microscopy that permits observation of nanoscopic features on solid surfaces under a liquid or solution environment. This allows in Situ measurement of important chemical transformations such as crystal growth and dissolution. Further, the microscope can access not only an accurate height measurement of surface topography, important to deduce structural elements, but also the forces involved during nanoscopic processes. We have discovered that it is possible to use these features to "illuminate" critical nanoscopic chemical events at crystal surfaces and at the same time extract the associated energies and unstitch the details of the stepwise mechanism of growth and dissolution. This approach has been developed using nanoporous crystals of the heterogeneous catalyst zeolite L; however, in principle the approach could be adapted to many crystal growth problems.

  • 8. Brent, Rhea
    et al.
    Stevens, Sam M.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Anderson, Michael W.
    Coaxial Core Shell Overgrowth of Zeolite L - Dependence on Original Crystal Growth Mechanism2010In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, no 12, p. 5182-5186Article in journal (Refereed)
    Abstract [en]

    In this study, the first reported core-shell material combining zeolite L (LTL) and barium-exchanged zeolite L (Ba-LTL) is described The use of atomic force microscopy to probe the LTL surface growth mechanism was employed to understand the growth pattern of the resultant Ba-LTL coaxial overgrowth layer Additionally the dependence of the original crystal surface on the resulting habit of the Ba-LTL core-shell layer is explained High-resolution scanning electron microscopy (HRSEM) was employed to observe the fine detail of the Ba-LTL layer, and cross-sectional polishing was used to view the boundary between the two crystalline materials

  • 9. Brouwer, Darren H.
    et al.
    Cadars, Sylvian
    Eckert, Juergen
    Liu, Zheng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Chmelka, Bradley F.
    A General Protocol for Determining the Structures of Molecularly Ordered but Noncrystalline Silicate Frameworks2013In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 135, no 15, p. 5641-5655Article in journal (Refereed)
    Abstract [en]

    A general protocol is demonstrated for determining the structures of molecularly ordered but noncrystalline solids, which combines constraints provided by X-ray diffraction (XRD), one- and two-dimensional solid-state nuclear magnetic resonance (NMR) spectroscopy, and first-principles quantum chemical calculations. The approach is used to determine the structure(s) of a surfactant-directed layered silicate with short-range order in two dimensions but without long-range periodicity in three-dimensions (3D). The absence of long-range 3D molecular order and corresponding indexable XRD reflections precludes determination of a space group for this layered silicate. Nevertheless, by combining structural constraints obtained from solid-state Si-29 NMR analyses, including the types and relative populations of distinct Si-29 sites, their respective Si-29-O-Si-29 connectivities and separation distances, with unit cell parameters (though not space group symmetry) provided by XRD, a comprehensive search of candidate framework structures leads to the identification of a small number of candidate structures that are each compatible with all of the experimental data. Subsequent refinement of the candidate structures using density functional theory calculations allows their evaluation and identification of best framework representations, based on their respective lattice energies and quantitative comparisons between experimental and calculated Si-29 isotropic chemical shifts and (2)J(Si-29-O-Si-29) scalar couplings. The comprehensive analysis identifies three closely related and topologically equivalent framework configurations that are in close agreement with all experimental and theoretical structural constraints. The subtle differences among such similar structural models embody the complexity of the actual framework(s), which likely contain coexisting or subtle distributions of structural order that are intrinsic to the material.

  • 10. Cheon, Jae Yeong
    et al.
    Kim, Taeyoung
    Choi, YongMan
    Jeong, Hu Young
    Kim, Min Gyu
    Sa, Young Jin
    Kim, Jaesik
    Lee, Zonghoon
    Yang, Tae-Hyun
    Kwon, Kyungjung
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Park, Gu-Gon
    Adzic, Radoslav R.
    Joo, Sang Hoon
    Ordered mesoporous porphyrinic carbons with very high electrocatalytic activity for the oxygen reduction reaction2013In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3, p. 2715-Article in journal (Refereed)
    Abstract [en]

    The high cost of the platinum-based cathode catalysts for the oxygen reduction reaction (ORR) has impeded the widespread application of polymer electrolyte fuel cells. We report on a new family of non-precious metal catalysts based on ordered mesoporous porphyrinic carbons (M-OMPC; M = Fe, Co, or FeCo) with high surface areas and tunable pore structures, which were prepared by nanocasting mesoporous silica templates with metalloporphyrin precursors. The FeCo-OMPC catalyst exhibited an excellent ORR activity in an acidic medium, higher than other non-precious metal catalysts. It showed higher kinetic current at 0.9 V than Pt/C catalysts, as well as superior long-term durability and MeOH-tolerance. Density functional theory calculations in combination with extended X-ray absorption fine structure analysis revealed a weakening of the interaction between oxygen atom and FeCo-OMPC compared to Pt/C. This effect and high surface area of FeCo-OMPC appear responsible for its significantly high ORR activity.

  • 11. Cho, Hae Sung
    et al.
    Deng, Hexiang
    Miyasaka, Keiichi
    Dong, Zhiyue
    Cho, Minhyung
    Neimark, Alexander V.
    Kang, Jeung Ku
    Yaghi, Omar M.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Graduate School of Energy, Environment, Water and Sustainability, South Korea.
    Extra adsorption and adsorbate superlattice formation in metal-organic frameworks2015In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 527, no 7579, p. 503-U193Article in journal (Refereed)
    Abstract [en]

    Metal-organic frameworks (MOFs) have a high internal surface area and widely tunable composition(1,2), which make them useful for applications involving adsorption, such as hydrogen, methane or carbon dioxide storage(3-9). The selectivity and uptake capacity of the adsorption process are determined by interactions involving the adsorbates and their porous host materials. But, although the interactions of adsorbate molecules with the internal MOF surface(10-17) and also amongst themselves within individual pores(18-22) have been extensively studied, adsorbate-adsorbate interactions across pore walls have not been explored. Here we show that local strain in the MOF, induced by pore filling, can give rise to collective and long-range adsorbate-adsorbate interactions and the formation of adsorbate superlattices that extend beyond an original MOF unit cell. Specifically, we use in situ small-angle X-ray scattering to track and map the distribution and ordering of adsorbate molecules in five members of the mesoporous MOF-74 series along entire adsorption-desorption isotherms. We find in all cases that the capillary condensation that fills the pores gives rise to the formation of 'extra adsorption domains'-that is, domains spanning several neighbouring pores, which have a higher adsorbate density than non-domain pores. In the case of one MOF, IRMOF-74-V-hex, these domains form a superlattice structure that is difficult to reconcile with the prevailing view of pore-filling as a stochastic process. The visualization of the adsorption process provided by our data, with clear evidence for initial adsorbate aggregation in distinct domains and ordering before an even distribution is finally reached, should help to improve our understanding of this process and may thereby improve our ability to exploit it practically.

  • 12. Cho, Hae Sung
    et al.
    Hill, Adam R.
    Cho, Minhyung
    Miyasaka, Keiichi
    Jeong, Kyungmin
    Anderson, Michael W.
    Kang, Jeung Ku
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Korea Advanced Institute of Science and Technology (KAIST), Republic of Korea; School of Physical Science and Technology, China.
    Directing the Distribution of Potassium Cations in Zeolite-LTL through Crown Ether Addition2017In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 17, no 9, p. 4516-4521Article in journal (Refereed)
    Abstract [en]

    We discover that the crystal morphology of zeolite-LTL could be modified by crown ether (21-crown-7, CE), where CE decreases the aspect ratio of zeolite-LTL while increasing the nucleation of domains on the (0001) face and hindering their growth along the c-axes. Moreover, the study using scanning electron microscopy supports that the ratio between the rates for generation of cancrinite columns and bridging cancrinite columns on the {10 (1) over bar0} face remains constant among the LTL frameworks with different amounts of CE molecules. In addition, X-ray diffraction analysis shows that potassium cations redistribute into pore cavities (t-lil) from cancrinite cages (t-can) and t-ste cages by the strong interactions between potassium and CE as the amount of CE molecules is increased. Additionally, Monte Carlo simulations clarify that stabilization of the t-lil cage via the redistribution of potassium cations at high CE concentration is attributed to the dominant effect in the crystal morphology changes observed. To understand the catalytic and adsorption properties of zeolites, it is important to investigate their structure/property relationships. Especially, studying the morphology of an anisotropic zeolite crystals has been of great interest because of the strong influence on controlling its properties. Thus, morphological control of the material with a particular crystallographic direction is highly desirable to obtain maximum properties for applications.

  • 13. Cho, Hae Sung
    et al.
    Miyasaka, Keiichi
    Kim, Hyungjun
    Kubota, Yoshiki
    Takata, Masaki
    Kitagawa, Susumu
    Ryoo, Ryong
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Study of Argon Gas Adsorption in Ordered Mesoporous MFI Zeolite Framework2012In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 48, p. 25300-25308Article in journal (Refereed)
    Abstract [en]

    An ordered mesoporous MFI zeolite material (Meso-MFI) was prepared by using CMK-type mesoporous carbons as a hard template. The Meso-MFI exhibits both structural and adsorption differences compared to the conventional bulk MFI zeolite. To study the argon (Ar) adsorption process in Meso-MFI, an in situ gas adsorption powder X-ray diffraction (XRD) analysis was performed using synchrotron X-ray source. Structural rearrangement of the mesoporous MFI zeolite upon Ar adsorption at low temperature (83 K) was intensively studied together with Ar adsorption process in Meso-MFI. We observed that a structural transition of the Meso-MFI zeolite framework from monoclinic (P2(1)/n) to orthorhombic (Pnma) occurred at around 126 Pa at 83 K. Positions of Ar atoms are determined as a function of the Ar gas pressure through Rietveld refinement of powder XRD data. Ar atoms are observed at straight channels, sinusoidal channels, and the intersection of these channels at low pressure. As gas pressure increases, Ar atoms in the pore intersection are pulled off from the intersection toward the straight and sinusoidal channels. The pore shape of the straight channel is changed accordingly with the amount of adsorbed Ar atoms within the pores from circular to oval. These results indicate that Ar adsorption induces not only continuous rearrangement of framework atoms but also symmetry change in the Meso-MFI. A molecular simulation study combined with Rietveld refinement of in situ XRD data provided a full understanding of the adsorption process of Ar in Meso-MFI.

  • 14. Cho, Kanghee
    et al.
    Ryoo, Ryong
    Asahina, Shunsuke
    Xiao, Changhong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Klingstedt, Miia
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Umemura, Ayako
    Anderson, Michael W.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Mesopore generation by organosilane surfactant during LTA zeolite crystallization investigated by high-resolution SEM and Monte Carlo simulation2011In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 13, no 4, p. 750-756Article in journal (Refereed)
    Abstract [en]

    The crystallization of LTA zeolite under a hydrothermal synthesis condition that contained a quaternary ammonium-type organosilane surfactant was studied with X-ray powder diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and Monte Carlo simulation of the crystal growth. The hydrothermal reaction products were collected at various crystallization times, and investigated with XRD and HRSEM. The HRSEM images of the final zeolite products were taken as synthesized and also after cross-sectioning with an argon ion beam. The HRSEM investigation revealed presence of a disordered network of mesoporous channels that penetrated the microporous zeolite crystal. Unless the loading of the surfactant was exceedingly high, the microporous zeolite particles exhibited truncated cubic morphologies that were almost like single crystals, despite penetration by the mesopores. The outline of the zeolite particle became progressively rounded as the mesoporosity was increased according to the surfactant loading. The mesoporosity in the zeolite crystals was well maintained against crystal-ripening processes for 6 d. This result supports the fact that the organosilane surfactant micelles became incorporated inside the zeolite crystal as a mesopore generator during the crystallization process. Data from Monte Carlo simulation agreed with these experimental results.

  • 15. Choi, Minkee
    et al.
    Na, Kyungsu
    Kim, Jeongnam
    Sakamoto, Yasuhiro
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Ryoo, Ryong
    Stable single-unit-cell nanosheets of zeolite MFI as active and long-lived catalysts2009In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 461, no 7261, p. 246-249Article in journal (Refereed)
    Abstract [en]

    Zeolites-microporous crystalline aluminosilicates-are widely used in petrochemistry and fine-chemical synthesis(1-3) because strong acid sites within their uniform micropores enable size- and shape-selective catalysis. But the very presence of the micropores, with aperture diameters below 1 nm, often goes hand-in-hand with diffusion limitations(3-5) that adversely affect catalytic activity. The problem can be overcome by reducing the thickness of the zeolite crystals, which reduces diffusion path lengths and thus improves molecular diffusion(4,5). This has been realized by synthesizing zeolite nanocrystals(6), by exfoliating layered zeolites(7-9), and by introducing mesopores in the microporous material through templating strategies(10-17) or demetallation processes(18-22). But except for the exfoliation, none of these strategies has produced 'ultrathin' zeolites with thicknesses below 5 nm. Here we show that appropriately designed bifunctional surfactants can direct the formation of zeolite structures on themesoporous and microporous length scales simultaneously and thus yield MFI (ZSM-5, one of the most important catalysts in the petrochemical industry) zeolite nanosheets that are only 2 nm thick, which corresponds to the b-axis dimension of a single MFI unit cell. The large number of acid sites on the external surface of these zeolites renders them highly active for the catalytic conversion of large organic molecules, and the reduced crystal thickness facilitates diffusion and thereby dramatically suppresses catalyst deactivation through coke deposition during methanol-to-gasoline conversion. We expect that our synthesis approach could be applied to other zeolites to improve their performance in a range of important catalytic applications.

     

  • 16. Cubillas, Pablo
    et al.
    Gebbie, James T.
    Stevens, Sam M.
    Blake, Nicola
    Umemura, Ayako
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Anderson, Michael W.
    Atomic Force Microscopy and High Resolution Scanning Electron Microscopy Investigation of Zeolite A Crystal Growth. Part 2: In Presence of Organic Additives2014In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, no 40, p. 23092-23099Article in journal (Refereed)
    Abstract [en]

    The nanoscopic details of the crystal growth of zeolite. A in the presence of the organic modifiers. diethanolmaine (DEA) and triethanolamine (TEA) has been determined using a combination of atomic force microscopy (AFM) and high-resolution scanning electron microscopy (HRSEM) coupled with Monte Carlo simulations. Crystallization of zeolite A in the presence of TEA was faster than when the growing solution contained DEA. In addition, the morphology of the final zeolite A crystals depended on the type of organic molecule, with TEA producing crystals bound only by {100} facets and DEA leading to the formation of relatively large {110} faces. These features can be explained in terms of the relative Si/Al in the growing medium and its control due to the different affinity of the organic molecules to Al. In addition, synthesis Si/Al in the growing medium and its contorl due to the different affinity of the organic molecules to Al. In additon synthesis performed at 90 degrees C showed the apperance of {211} facets Careful review of the HRSEM and AFM images, in addition to comparion with the MC simulations, reveals that these are in fact pseudofacets products of the slow dissolution of the metastable zeolite. A crsytals. This proves that the final habit of the LTA crystals can be governed by very small changes in saturation of the growing medium, and control of this parameter can prove advantageous when designing crystals for industrial applications.

  • 17. Cubillas, Pablo
    et al.
    Stevens, Sam M.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Blake, Nicola
    Umemura, Ayako
    Chong, Chin B.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Anderson, Michael W.
    AFM and HRSEM Invesitigation of Zeolite A Crystal Growth. Part 1: In the Absence of Organic Additives2011In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, no 25, p. 12567-12574Article in journal (Refereed)
    Abstract [en]

    The crystallization of zeolite A by the verified synthesis method was studied by means of high-resolution scanning electron microscopy (HRSEM) and atomic force microscopy (AFM). These methods show an evolution in the growth mode of zeolite A from an adhesive type at the beginning of the synthesis (high supersaturation) to birth-and-spread growth at the end of the synthesis (low supersaturation). Additionally, HRSEM provides direct proof on the formation of zeolite A crystals at the surface of the amorphous gel and the aggregation of crystals at early stages of synthesis, which leads to intergrowth formation. For the first time, high-resolution AFM images were taken on the {110} and {111} faces of zeolite A. Growth on {110} faces takes place by a birth-and-spread mechanism, and the shape of the terraces is rectangular, with growth along the < 100 > directions being twice as fast as in the < 110 > directions. Growth on the {111} faces also takes place by a birth-and-spread mechanism via triangular-shaped terraces with edges parallel to < 110 > directions. Possible surface terminations for both faces are discussed, and crystal habit and surface topography are modeled by Monte Carlo simulations.

  • 18. Datta, Shuvo Jit
    et al.
    Khumnoon, Chutharat
    Lee, Zhen Hao
    Moon, Won Kyung
    Docao, Son
    Nguyen, Thanh Huu
    Hwang, In Chul
    Moon, Dohyun
    Oleynikov, Peter
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Graduate School of EEWS, KAIST, Korea; ShanghaiTech University, China.
    Yoon, Kyung Byung
    CO2 capture from humid flue gases and humid atmosphere using a microporous coppersilicate2015In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 350, no 6258, p. 302-+Article in journal (Refereed)
    Abstract [en]

    Capturing CO2 from humid flue gases and atmosphere with porous materials remains costly because prior dehydration of the gases is required. A large number of microporous materials with physical adsorption capacity have been developed as CO2-capturing materials. However, most of them suffer from CO2 sorption capacity reduction or structure decomposition that is caused by co-adsorbed H2O when exposed to humid flue gases and atmosphere. We report a highly stable microporous coppersilicate. It has H2O-specific and CO2-specific adsorption sites but does not have H2O/CO2-sharing sites. Therefore, it readily adsorbs both H2O and CO2 from the humid flue gases and atmosphere, but the adsorbing H2O does not interfere with the adsorption of CO2. It is also highly stable after adsorption of H2O and CO2 because it was synthesized hydrothermally.

  • 19. Deng, Hexiang
    et al.
    Grunder, Sergio
    Cordova, Kyle E.
    Valente, Cory
    Furukawa, Hiroyasu
    Hmadeh, Mohamad
    Gandara, Felipe
    Whalley, Adam C.
    Liu, Zheng
    Asahina, Shunsuke
    Kazumori, Hiroyoshi
    O'Keeffe, Michael
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Stoddart, J. Fraser
    Yaghi, Omar M.
    Large pore apertures in a series of metal organic frameworks2012In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 336, no 6084, p. 1018-1023Article in journal (Refereed)
    Abstract [en]

    We report a strategy to expand the pore aperture of metal-organic frameworks (MOFs) into a previously unattained size regime (>32 angstroms). Specifically, the systematic expansion of a well-known MOF structure, MOF-74, from its original link of one phenylene ring (I) to two, three, four, five, six, seven, nine, and eleven (II to XI, respectively), afforded an isoreticular series of MOF-74 structures (termed IRMOF-74-I to XI) with pore apertures ranging from 14 to 98 angstroms. All members of this series have non-interpenetrating structures and exhibit robust architectures, as evidenced by their permanent porosity and high thermal stability (up to 300 degrees C). The pore apertures of an oligoethylene glycol-functionalized IRMOF-74-VII and IRMOF-74-IX are large enough for natural proteins to enter the pores.

  • 20. Doi, Yoji
    et al.
    Takai, Azusa
    Sakamoto, Yasuhiro
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yamauchi, Yusuke
    Kuroda, Kazuyuki
    Tailored synthesis of mesoporous platinum replicas using double gyroid mesoporous silica (KIT-6) with different pore diameters via vapor infiltration of a reducing agent2010In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 46, no 34, p. 6365-6367Article in journal (Refereed)
    Abstract [en]

    We demonstrate facile synthesis of mesoporous Pt replicas using double gyroid mesoporous silica (KIT-6) with different pore diameters via vapor infiltration of a reducing agent. Through controlling the complementary pore size, it becomes possible to selectively deposit Pt into one side pore of the Ia (3) over bard bicontinuous structure, thereby forming a mesoporous Pt replica with relatively large mesopores (over 10 nm).

  • 21. Fan, Chaxing
    et al.
    Qiu, Huibin
    Ruan, Juanfang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Yan, Yong
    Wei, Zhixiang
    Che, Shunai
    Formation of chiral mesopores in conducting polymers by chiral lipid ribbon templating and “seeding” route2008In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 18, no 18, p. 2699-2707Article in journal (Refereed)
    Abstract [en]

    Conducting polymer nanofibers with controllable chiral mesopores in the size, the shape, and handedness have been synthesized by chiral lipid ribbon templating and “seeding” route. Chiral mesoporous conducting poly(pyrrole) (CMPP) synthesized with very small amount of chiral amphiphilic molecules (usually < 3%) has helically twisted channels with well-defined controllable pore size of 5–20 nm in central axis of the twisted fibers. The structure and chirality of helical mesopores have been characterized by high-resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM) and electron tomography. The average pore diameters of chiral mesopores were approximately estimated from the N2 adsorption–desorption data and calculated by the conversion calculation from helical ribbons to a rectangular straight tape. The pore size of CMPP has been controlled by choosing different alkyl chain lengths of chiral lipid molecules or precisely adjusting the H2O/EtOH volume ratio.

  • 22. Galarneau, A
    et al.
    Iapichella, J
    Bonhomme, K
    Di Renzo, F
    Kooyman, P
    Terasaki, O
    Stockholm University.
    Fajula, F
    Controlling the morphology of mesostructured silicas by pseudomorphic transformation: A route towards applications2006In: Advanced Functional Materials, Vol. 16, p. 1657-1667Article in journal (Refereed)
  • 23. Gao, CB
    et al.
    Qui, HB
    Zeng, W
    Sakamoto, Y
    Stockholm University.
    Terasaki, O
    Stockholm University.
    Sakamoto, K
    Shen, Q
    Che, SA
    Formation mechanism of anionic surfactant-templated mesoporous silica2006In: Chemistry of Materials, Vol. 18, p. 3904-3914Article in journal (Refereed)
  • 24. Gao, CB
    et al.
    Sakamoto, Y
    Stockholm University.
    Sakamoto, K
    Terasaki, O
    Stockholm University.
    Che, SA
    Synthesis and characterization of mesoporous silica AMS-10 with bicontinuous cubic Pn3m symmetry2006In: Angewandte Chemie-International Edition, Vol. 45, p. 4295-4298Article in journal (Refereed)
  • 25. Gao, CB
    et al.
    Sakamoto, Y
    Stockholm University.
    Sakamoto, K
    Terasaki, O
    Stockholm University.
    Che, SN
    Synthesis and characterization of mesoporous silica AMS-10 with bicontinuous cubic Pn-3m symmetry2006In: Angewandte Chemie-International Edition, Vol. 45, p. 4295-4298Article in journal (Refereed)
  • 26.
    Gao, Chuanbo
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Izquierdo-Barba, Isabel
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Nakase, Ikuhiko
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Mesostructured silica based delivery system for a drug with a peptide as a cell-penetrating vector2009In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 122, no 1-3, p. 201-207Article in journal (Refereed)
    Abstract [en]

    A drug delivery system using mesostructured silica as a reservoir has been developed for the storage and controlled release of a drug with a cell-penetrating peptide (CPP) as a vector. We use fluorescein isothiocyanate (FITC) as the drug model and octaarginine (R8) as a vector to endow the drug with cell-penetrating property. The mesostructured silica reservoir system was prepared by using a one-pot liquid?crystal templating method, which is suitable for the encapsulation of intact FITC-R8 conjugates and sustained release of drugs without hampering their properties. The hydrophobic poly(propyl oxide) (PPO) shell of the pore-filling Pluronic F127 and the electrostatic interaction between R8 and siloxide ions on the pore walls act as the diffusion-limiting factors of the FITC-R8 conjugate. A sigmoidal in vitro release of FITC-R8 from mesostructured silica into phosphate buffered saline (PBS, pH 7.4) was observed and the typical release duration was 5 days at 37 ‹C. Release from the reservoir yielded significant elongation in duration of the FITC signals in DU145 cells by confocal microscopic analysis, compared with a single administration of FITC-R8.

     

  • 27.
    Gao, Chuanbo
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Sakamoto, Yasuhiro
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Che, Shunai
    Formation of Diverse Mesophases Templated by a Diprotic Anionic Surfactant2008In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 14, no 36, p. 11423-11428Article in journal (Refereed)
    Abstract [en]

    The synthesis system for mesophase formation, using the diprotic anionic surfactant N-myristoyl-l-glutamic acid (C14GluA) as the structuredirecting agent (SDA) and N-trimethoxylsilylpropyl-N,N,N-trimethylammonium chloride (TMAPS) as the co-structure-directing agent (CSDA), has been investigated and a full-scaled synthesis-field diagram is presented. In this system we have obtained mesophases including three-dimensional (3D) micellar cubic Fm-3m, Pm-3n, Fd-3m, micellar tetragonal P42/mnm, two-dimensional (2D) hexagonal p6mm and bicontinuous cubic Pn-3m, by varying the C14GluA/NaOH/TMAPS composition ratios. From the diagram it can be concluded that the mesophase formation is affected to a high degree by the organic/inorganicinterface curvature and the mesocage–mesocage electrostatic interaction. Bicontinuous cubic and 2D-hexagonalphases were found in the low organic/inorganic-interface curvature zones, whereas micellar cubic and tetragonal mesophases were found in the high organic/inorganic-interface curvature zones. Formation of cubic Fm-3m and tetragonal P42/mnm was favoured in highly alkaline zones with strong mesocage–mesocage interactions, and formation of cubic Pm-3n and Fd-3m was favoured with moderate mesocage–mesocage interactions in the less alkaline zones of the diagram.

  • 28. Gramm, F
    et al.
    Baerlocher, C
    McCusker, LB
    Warrender, SJ
    Wright, PA
    Han, B
    Hong, SB
    Liu, Z
    Ohsuna, T
    Terasaki, O
    Stockholm University.
    Complex zeolite structure solved by combining powder diffraction and electron microscopy2006In: Nature, Vol. 444, p. 79-81Article in journal (Refereed)
  • 29. Gu, Dong
    et al.
    Bongard, Hans
    Meng, Yan
    Miyasaka, Keiichi
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zhang, Fuqiang
    Deng, Yonghui
    Wu, Zhangxiong
    Feng, Dan
    Fang, Yin
    Tu, Bo
    Schueth, Ferdi
    Zhao, Dongyuan
    Growth of Single-Crystal Mesoporous Carbons with Im(3)over-barm Symmetry2010In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 22, no 16, p. 4828-4833Article in journal (Refereed)
    Abstract [en]

    Highly ordered mesoporous carbon FDU-16 rhombic dodecahedral single crystals with body-centered cubic structure (space group Im (3) over barm) have been successfully synthesized by employing an organic-organic assembly of triblock copolymer Pluronic F127 (EO106PO70EO106) and phenol/formaldehyde resol in basic aqueous solution. Synthetic factors (including reaction time, temperature, and stirring rate) are explored for controlling the formation of rhombic dodecahedral single crystals. The optimal stirring rate and the reaction temperature are 300 +/- 10 rpm and similar to 66 degrees C, respectively. High-resolution scanning electron microscopy (HRSEM), scanning transmission electron microscopy (STEM), and ultramicrotomy are applied to study the fine structures of the carbon single crystals. The mesopores are arranged in body-centered cubic symmetry throughout the entire particle. Surface steps are clearly observed in the {110} surface, which suggests a layer-by-layer growth of the mesoporous carbon FDU-16 single crystals. Cryo-SEM results from the reactant solution confirm the formation of resol/F127 unit micelles, further supporting the layer-by-layer growth process. The mesoporous carbon FDU-16 single crystals grow up to the final size of 2-4 mu m within 2 days. These findings may have consequences for the growth mechanism of other carbon materials in aqueous solution; moreover, the high-quality single crystals also have potential applications in nanodevice technologies.

  • 30. Gu, Dong
    et al.
    Schmidt, Wolfgang
    Pichler, Christian M.
    Bongard, Hans-Josef
    Spliethoff, Bernd
    Asahina, Shunsuke
    Cao, Zhengwen
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). ShanghaiTech School of Physical Science and Technology, P.R. China.
    Schueth, Ferdi
    Surface-Casting Synthesis of Mesoporous Zirconia with a CMK-5-Like Structure and High Surface Area2017In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 56, no 37, p. 11222-11225Article in journal (Refereed)
    Abstract [en]

    About 15 years ago, the Ryoo group described the synthesis of CMK-5, a material consisting of a hexagonal arrangement of carbon nanotubes. Extension of the surface casting synthesis to oxide compositions, however, was not possible so far, in spite of many attempts. Here it is demonstrated, that crystalline mesoporous hollow zirconia materials with very high surface areas up to 400 m(2) g(-1), and in selected cases in the form of CMK-5-like, are indeed accessible via such a surface casting process. The key for the successful synthesis is an increased interaction between the silica hard template surface and the zirconia precursor species by using silanol group-rich mesoporous silica as a hard template. The surface areas of the obtained zirconias exceed those of conventionally hard-templated ones by a factor of two to three. The surface casting process seems to be applicable also to other oxide materials.

  • 31. Han, Lu
    et al.
    Miyasaka, Keiichi
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Graduate School of EEWS, WCU Energy Science & Engineering, Republic of Korea.
    Electron Crystallography2014In: Structure from Diffraction Methods / [ed] Duncan W. Bruce, Dermot O'Hare, Richard I. Walton, Chichester: John Wiley & Sons, 2014, p. 201-258Chapter in book (Refereed)
    Abstract [en]

    A transmission electron microscope (TEM) can provide an electron diffraction pattern on the back focal plane of the objective lens and can supply real-space information through images on the image plane. X-ray crystallography, using X-ray diffraction (XRD) with either a powder or a single-crystal diffractometer, is the most precise and most popular method of structural analysis. However, structure determination by powder XRD has its limitations. Due to this, electron crystallography (EC), which is the focus of this chapter,  is the only possible technique by which to solve/characterise the crystal structure. The chapter discusses the relationship between crystal structure and TEM images. It describes in detail, the various materials including 1D atomistic crystal, solved by EC methods. The chapter also discusses other TEM techniques such as high-angle annular dark-field imaging (HAADF) and electron tomography.

  • 32. Han, Lu
    et al.
    Miyasaka, Keiichi
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Che, Shunai
    Evolution of Packing Parameters in the Structural Changes of Silica Mesoporous Crystals: Cage-Type, 2D Cylindrical, Bicontinuous Diamond and Gyroid, and Lamellar2011In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 133, p. 11524-11533Article in journal (Refereed)
    Abstract [en]

    Cage-type, two-dimensional (2D) cylindrical hexagonal (C), bicontinuous diamond (D), bicontinuous gyroid (G), and one-dimensional (1D) lamellar (L) structures of silica mesoporous crystals (SMCs) were obtained by using the anionic surfactant N-stearoyl-L-glutamic acid (C(18)GluA) as a template in the presence of the nonionic surfactant C(16)(EO)(10) (Brij-56). The mesostructures were controlled by the organic/inorganic interface curvature change induced by Brij-56. A synthesis-field diagram showed that the mesostructure changed in the sequence cage-type -> C -> intergrowth of C and D -> intergrowth of C and G -> D -> G -> L with increase of the amount of Brij-56. Mixed micelles were formed by the anionic and nonionic surfactants, the packing parameter g of which increased with increasing the addition amount of nonionic surfactant and the reaction temperature. The local g parameter was obtained from electron crystallography reconstruction results by calculating mean curvatures and Gaussian curvatures from the equi-electrostatic potential surface. The intergrowth of C and D and two kinds of intergrowth of C and G are also discussed.

  • 33. Han, Lu
    et al.
    Ohsuna, Tetsu
    Liu, Zheng
    Alfredsson, Viveka
    Kjellman, Tomas
    Asahina, Shunsuke
    Suga, Mitsuo
    Ma, Yanhang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Oleynikov, Peter
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Miyasaka, Keiichi
    Mayoral, Alvaro
    Diaz, Isabel
    Sakamoto, Yasuhiro
    Stevens, Sam M.
    Anderson, Michael W.
    Xiao, Changhong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Fujita, Nobuhisa
    Garcia-Bennett, Alfonso
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yoon, Kyung Byung
    Che, Shunai
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Korea Advanced Institute of Science & Technology (KAIST), South Korea.
    Silica-Based Nanoporous Materials2014In: Zeitschrift für Anorganische und Allgemeines Chemie, ISSN 0044-2313, E-ISSN 1521-3749, Vol. 640, no 3-4, p. 521-536Article, review/survey (Refereed)
    Abstract [en]

    Ordered nanoporous structures are among the most fascinating and industrially important materials currently in use. The archetypal zeolite material has now been joined by an eclectic array of new structures that exhibit porosity over a wide range of length scales and with order/disorder expressed in a multitude of ways. This raises the bar in terms of characterization and extends a real challenge to the scientific community to fully understand the properties and potential future applications of such materials. In this review we discuss the importance of modern microscopy tools combined with diffraction in this endeavour and show how the details of even the most complex quasi-crystalline nanoporous architectures can be elucidated. We show by using the appropriate spherical aberration (C-s) corrections in scanning transmission electron microscopy it is possible to decipher all the individual silicon and aluminum atoms in a zeolite structure. Automated routines for using large electron diffraction datasets for crystal structure determination of nanocrystals is described making the need for large single crystal synthesis less-and-less important. The power of complementary combinations of surface tools such as atomic force microscopy and high-resolution scanning electron microscopy is discussed to elucidate crystal growth mechanisms. For mesoporous materials synthesized from self-organized organic mesophases electron microscopy reveals the details of the complex hierarchy of porosity so crucial for the functional performance of the structure.

  • 34.
    Han, Lu
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Ruan, Juanfang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Li, Yongsheng
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Che, Shunai
    Synthesis and Characterization of the Amphoteric Amino Acid Bifunctional Mesoporous Silica2007In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 19, no 11, p. 2860-2867Article in journal (Refereed)
  • 35.
    Han, Lu
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Sakamoto, Yasuhiro
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Che, Shunai
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Insight Into the Defects of Cage-Type Silica Mesoporous Crystals with Fd(3)over-arm Symmetry: TEM Observations and a New Proposal of "Polyhedron Packing" for the Crystals  2009In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, no 12, p. 2818-2825Article in journal (Refereed)
  • 36.
    Han, Lu
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Sakamoto, Yasuhiro
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Li, Y.
    Che, S.
    Synthesis of carboxylic group functionalized mesoporous silicas (CFMSs) with various structures2007In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 17, p. 1216-1221Article in journal (Refereed)
  • 37. Han, Lu
    et al.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Che, Shunai
    Carboxylic group functionalized ordered mesoporous silicas2011In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 30, p. 11033-11039Article in journal (Refereed)
    Abstract [en]

    Many research efforts have focused on the synthesis of organic and inorganic hybrid ordered mesoporous silicas (MSs) with functionalization of the exterior and/or interior surfaces aiming for applications in separation, adsorption, catalysis, drug delivery, and nanotechnology. Among the organic groups, the carboxylic group is a particularly useful reactive group for many applications. This article provides a brief overview of the carboxylic group functionalized MSs and the recent progress in synthetic strategies and applications have been reviewed.

  • 38. Hmadeh, Mohamad
    et al.
    Lu, Zheng
    Liu, Zheng
    Gandara, Felipe
    Furukawa, Hiroyasu
    Wan, Shun
    Augustyn, Veronica
    Chang, Rui
    Liao, Lei
    Zhou, Fei
    Perre, Emilie
    Ozolins, Vidvuds
    Suenaga, Kazu
    Duan, Xiangfeng
    Dunn, Bruce
    Yamamto, Yasuaki
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Yaghi, Omar M.
    New porous crystals of extended metal catecholates2012In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 24, no 18, p. 3511-3513Article in journal (Refereed)
  • 39.
    Izquierdo-Barba, Isabel
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Kupferschmidt, Natalia
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Schmidtchen, Artur
    Malmsten, Martin
    Vallet-Regí, Maria
    Incorporation of antimicrobial compounds in mesoporous silica film monolith2009In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 30, no 29, p. 5729-5736Article in journal (Refereed)
    Abstract [en]

    : Incorporation of the antimicrobial peptide LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES), as well as low molecular weight antimicrobial chlorhexidine, into mesoporous silica was obtained using an EISA one-pot synthesis method. FTIR confirmed efficient encapsulation of both LL-37 and chlorhexidine into mesoporous silica, while XRD and TEM showed that antimicrobial agent incorporation can be achieved without greatly affecting the structure of the mesoporous silica. The modified mesoporous silica released LL-37 and chlorhexidine slowly, reaching maximum release after about 200 h. The release rate could also be controlled through incorporation of SH groups in the pore walls, adding to pore hydrophobicity and reducing the release rate by about 50% compared to the unmodified mesoporous silica. Mesoporous silica containing either LL-37 or chlorhexidine displayed potent bactericidal properties against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. While chlorhexidine-loaded mesoporous silica displayed an accompanying high toxicity, as judged from hemolysis, LDH release, and MTT assay, the corresponding material containing LL-37 showed very low toxicity by all these assays, comparable to that observed for mesoporous silica in the absence of antibacterial drug, as well as to the negative controls in the respective assays. Mesoporous silica containing LL-37 therefore holds potential as an implantable material or a surface coating for such materials, as it combines potent bactericidal action with low toxicity, important features for controlling implant-related infections, e.g., for multi-resistant pathogens or for cases where access to the infection site of systemically administered antibiotics is limited due to collagen capsule formation or other factors.

     

  • 40. Jin, HY
    et al.
    Liu, Z
    Ohsuna, T
    Terasaki, O
    Stockholm University.
    Inoue, Y
    Sakamoto, K
    Nakanishi, T
    Ariga, K
    Che, SN
    Control of morphology and helicity of chiral mesoporous silica2006In: Advanced Materials, Vol. 18, p. 593-Article in journal (Refereed)
  • 41.
    Johansson, Mikael
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Purse, Byron W.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Terasak, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Aerobic Oxidations Catalyzed by Zeolite-Encapsulated Cobalt Salophen2008In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 350, no 11-12, p. 1807-1815Article in journal (Refereed)
    Abstract [en]

    Cobalt salophen was encapsulated in a series of zeolites with a wide variation of the silicon-to-aluminium atomic ratio and with different cations. The zeolite-cobalt salophen catalysts were prepared using the “ship-in-a-bottle technique” where the complex was synthesized in the super cage of the zeolite and therefore locked into the pocket. The encapsulated catalysts were then tested in the aerobic oxidation of hydroquinone to p-benzoquinone; the best encapsulated catalyst was shown to be an efficient electron-transfer mediator in a palladium-catalyzed aerobic oxidative carbocyclization.

  • 42. Kjellman, Tomas
    et al.
    Asahina, Shunsuke
    Schmitt, Julien
    Imperor-Clerc, Marianne
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Korea Advanced Institute of Science & Technology (KAIST), South Korea.
    Alfredsson, Viveka
    Direct Observation of Plugs and Intrawall Pores in SBA-15 Using Low Voltage High Resolution Scanning Electron Microscopy and the Influence of Solvent Properties on Plug-Formation2013In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 25, no 20, p. 4105-4112Article in journal (Refereed)
    Abstract [en]

    Through the use of low voltage high resolution scanning electron microscopy (LV-HRSEM) we have studied the fine details of the intricate pore structure of SBA-15. Intrawall pores and deviations from the ideal and uniform cylindrical pores are clearly observed, and we report for the first time the direct observation of plugs in the pores. N-2-sorption measurements confirm their existence. LV-HRSEM provides an opportunity to quantify the frequency of occurrence of plugs within the pore structure. The rate of mesophase formation, followed with in situ small angle X-ray scattering (SAXS) under different solvent conditions, is shown to have a significant influence on the development of plugs and how frequently they occur. We suggest a mechanism explaining the existence of the plugs, providing means for a better understanding and control over material properties.

  • 43.
    Klingstedt, Miia
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Miyasaka, Keiichi
    Kimura, Kosuke
    Gu, Dong
    Wan, Ying
    Zhao, Dongyuan
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Advanced electron microscopy characterization for pore structure of mesoporous materials; a study of FDU-16 and FDU-182011In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 35, p. 13664-13671Article in journal (Refereed)
    Abstract [en]

    We present a comprehensive analysis for pore structures of cage-type ordered mesoporous carbons (OMCs) using various electron microscopy techniques in addition to conventional nitrogen adsorption isotherm studies. The benefits and drawbacks of these techniques are evaluated, and it is shown that they are complementary to each other. Knowledge of the structural properties, pore sizes, and connectivity gives insight into the synthesis strategies and how they are affecting the material properties that are useful within the possible applications. Herein, focus is put on the two OMCs with Im (3) over barm and Fm (3) over barm symmetries specified by FDU-16 and FDU-18. The central techniques used in this study are high resolution scanning electron microscopy combined with cross-section polisher and three-dimensional reconstruction methods (electron tomography and electron crystallography) based on transmission electron microscopy observations.

  • 44.
    Klingstedt, Miia
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sundberg, Margareta
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Haigh, Sara
    Kirkland, Angus
    Gruner, Daniel
    De Backer, Annick
    Van Aert, Sandra
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Exit wave reconstruction from focal series of HRTEM images, single crystal XRD and total energy studies on SbxWO3+y (x~0.11)Article in journal (Refereed)
  • 45. Li, Cuiling
    et al.
    Dag, Oemer
    Dao, Thang Duy
    Nagao, Tadaaki
    Sakamoto, Yasuhiro
    Kimura, Tatsuo
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Graduate School of EEWS, KAIST, Korea.
    Yamauchi, Yusuke
    Electrochemical synthesis of mesoporous gold films toward mesospace-stimulated optical properties2015In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 6, article id 6608Article in journal (Refereed)
    Abstract [en]

    Mesoporous gold (Au) films with tunable pores are expected to provide fascinating optical properties stimulated by the mesospaces, but they have not been realized yet because of the difficulty of controlling the Au crystal growth. Here, we report a reliable soft-templating method to fabricate mesoporous Au films using stable micelles of diblock copolymers, with electrochemical deposition advantageous for precise control of Au crystal growth. Strong field enhancement takes place around the center of the uniform mesopores as well as on the walls between the pores, leading to the enhanced light scattering as well as surface-enhanced Raman scattering (SERS), which is understandable, for example, from Babinet principles applied for the reverse system of nanoparticle ensembles.

  • 46. Li, HC
    et al.
    Sakamoto, Y
    Stockholm University.
    Terasaki, O
    Stockholm University.
    Thommes, M
    Che, SA
    Synthesis of carbon replicas of SBA-1 and SBA-7 mesoporous silicas2006In: Microporous and Mesoporous Materials, Vol. 95, p. 193-199Article in journal (Refereed)
  • 47. Li, Huachun
    et al.
    Sakamoto, Yasuhiro
    Liu, Zheng
    Ohsuna, Tetsu
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Thommes, Matthias
    Che, Shunai
    Mesoporous silicalite-1 zeolite crystals with unique pore shapes analogous to the morphology2007In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 106, no 03-jan, p. 174-179Article in journal (Refereed)
    Abstract [en]

    Thermal/hydrothermal stable silicalite-1 zeolite with high-porosity mesopores analogous to the crystal morphology has been synthesized by using large porous carbon (10-20 nm) as hard template originated from colloidal silica.

  • 48. Li, Yanbo
    et al.
    Zhang, Li
    Torres-Pardo, Almudena
    Gonzalez-Calbet, Jose M.
    Ma, Yanhang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Oleynikov, Peter
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry. Graduate School of EEWS, WCU, KAIST, Republic of Korea.
    Asahina, Shunsuke
    Shima, Masahide
    Cha, Dongkyu
    Zhao, Lan
    Takanabe, Kazuhiro
    Kubota, Jun
    Domen, Kazunari
    Cobalt phosphate-modified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency2013In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 4, article id 2566Article in journal (Refereed)
    Abstract [en]

    Spurred by the decreased availability of fossil fuels and global warming, the idea of converting solar energy into clean fuels has been widely recognized. Hydrogen produced by photoelectrochemical water splitting using sunlight could provide a carbon dioxide lean fuel as an alternative to fossil fuels. A major challenge in photoelectrochemical water splitting is to develop an efficient photoanode that can stably oxidize water into oxygen. Here we report an efficient and stable photoanode that couples an active barium-doped tantalum nitride nanostructure with a stable cobalt phosphate co-catalyst. The effect of barium doping on the photoelectrochemical activity of the photoanode is investigated. The photoanode yields a maximum solar energy conversion efficiency of 1.5%, which is more than three times higher than that of state-of-the-art single-photon photoanodes. Further, stoichiometric oxygen and hydrogen are stably produced on the photoanode and the counter electrode with Faraday efficiency of almost unity for 100 min.

  • 49. Liu, Yong
    et al.
    Jia, Chun-Jiang
    Yamasaki, Jun
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Schueth, Ferdi
    Highly Active Iron Oxide Supported Gold Catalysts for CO Oxidation: How Small Must the Gold Nanoparticles Be?2010In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 49, no 33, p. 5771-5775Article in journal (Refereed)
  • 50. Liu, Yuzhong
    et al.
    Ma, Yanhang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zhao, Yingbo
    Sun, Xixi
    Gándara, Felipe
    Furukawa, Hiroyasu
    Liu, Zheng
    Zhu, Hany
    Zhu, Chenhui
    Suenaga, Kazutomo
    Oleynikov, Peter
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Alshammari, Ahmad S.
    Zhang, Xiang
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). ShanghaiTech University, China.
    Yaghi, Omar M.
    Weaving of organic threads into a crystalline covalent organic framework2016In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 351, p. 365-369Article in journal (Refereed)
    Abstract [en]

    A three-dimensional covalent organic framework (COF-505) constructed from helical organic threads, designed to be mutually weaving at regular intervals, has been synthesized by imine condensation reactions of aldehyde functionalized copper(I)-bisphenanthroline tetrafluoroborate, Cu(PDB)2(BF4), and benzidine (BZ). The copper centers are topologically independent of the weaving within the COF structure and serve as templates for bringing the threads into a woven pattern rather than the more commonly observed parallel arrangement. The copper(I) ions can be reversibly removed and added without loss of the COF structure, for which a tenfold increase in elasticity accompanies its demetalation. The threads in COF-505 have many degrees of freedom for enormous deviations to take place between them, throughout the material, without undoing the weaving of the overall structure.

123 1 - 50 of 107
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