Hydrogen Storage in a Prototypical Zeolitic Imidazolate Framework-8

William Penn University, Filadelfia, Pennsylvania, United States
Journal of the American Chemical Society (Impact Factor: 12.11). 05/2007; 129(17):5314-5. DOI: 10.1021/ja0691932
Source: PubMed


Using the difference Fourier analysis of neutron powder diffraction data along with first-principles calculations, we reveal detailed structural information such as methyl group orientation, hydrogen adsorption sites, and binding energies within the nanopore structure of ZIF8 (Zn(MeIM)(2)). Surprisingly, the two strongest adsorption sites that we identified are both directly associated with the organic linkers, instead of the ZnN4 clusters, in strong contrast to classical MOFs, where the metal-oxide clusters are the primary adsorption sites. These observations are important and hold the key to optimizing this new class of ZIF materials for practical hydrogen storage applications. Finally, at high concentration H-2-loadings, ZIF8 structure is capable of holding up to 28 H-2 molecules (i.e., 4.2 wt %) in the form of highly symmetric novel three-dimensional interlinked H-2-nanoclusters with relatively short H-2-H-2 distances compared to solid H-2. Hence, ZIF compounds with robust chemical stability can be also an ideal template host-material to generate molecular nanostructures with novel properties.

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    • "In particular, zeolitic imidazolate frameworks (ZIFs) are a subclass of metal organic frameworks with zeolite or zeolitelike topologies, which possess several extraordinary features, such as chemical robustness and thermal stability [7] [8]. Among various ZIFs materials, ZIF-8 which is a tetrahedral framework formed by zinc ions and imidazolate ligands with sodalite topology is the most extensively studied [9]. Substantial works have been done on synthesizing ZIF-8 for gas sorption/separation, catalysis, electrochemical biosensor, as well as functionalized thin films, etc. [10] [11] [12] [13] [14]. "
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    ABSTRACT: In this study, zeolitic imidazolate framework-8 (ZIF-8) nanosorbent was successfully synthesized via a facile method at room temperature. The ZIF-8 nanoparticles were characterized by nitrogen sorption, powder X-ray diffraction, field emission scanning electron microscope, transmission electron microscopy and Zeta potential. The synthesized ZIF-8 nanoparticles exhibited a high surface area of 1063.5 m2/g and were of 200–400 nm in particle size. The kinetic and isotherm data of arsenic adsorption on ZIF-8 were well fitted by pseudo-second-order and Langmuir models, respectively. The maximal adsorption capacities of As(III) and As(V) were of 49.49 and 60.03 mg/g, respectively, at T = 25 °C and pH 7.0. The ZIP-8 nanoparticles were stable at neutral and basic conditions. However, large amounts of Zn2+ were released into water from the sorbent at acidic condition, which dramatically hindered the adsorption of arsenic. SO42− and NO3− had no significant effect on the arsenic adsorption while the adsorption was significantly inhibited by PO43− and CO32−. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis revealed that electrostatic attraction and hydroxyl and amine groups on ZIF-8 surface played vital roles in the adsorption process.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 10/2014; 465. DOI:10.1016/j.colsurfa.2014.10.023 · 2.75 Impact Factor
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    • ", Covalent Triazine based Frameworks (CTFs) [10] and Zeolitic Imidazolate Frameworks (ZIFs) [11] are promising candidates as hydrogen storage materials. This is due to their great number of hydrogen adsorption sites, tunable pore sizes to trap hydrogen molecules on the host material's surface and ease of hydrogen adsorption/desorption from the host materials . "
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    ABSTRACT: This work deals with the investigations of hydrogen adsorption energies of the Li func-tionalized Covalent Organic Framework-366 (COF-366) by using the density functional theory method. Based on total energy calculations, it was found that Li atom is preferen-tially trapped at the center site of the tetra(p-amino-phenyl) porphyrin and the onN site of a terephthaldehyde chain. Moreover, hydrogen adsorption energies per H 2 for 1e3 H 2 loadings range from 0.03 to 0.22 eV. According to ab initio molecular dynamics simulations, our results found that hydrogen capacities of Li functionalized COF-366 at ambient pres-sure are 2.06, 1.58, and 1.05 wt% for 77, 150 and 298 K, respectively.
    International Journal of Hydrogen Energy 11/2013; 38(33):14276–14280. DOI:10.1016/j.ijhydene.2013.08.102 · 3.31 Impact Factor
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    • "The zeolitic imidazolate framework (ZIF) materials have zeolitelike topologies and belong to an important class of metal–organic framework (MOF) materials with interesting adsorption, separation and catalytic properties [9] [10] [11] [12] [13] [14]. However, reports of magnetic core–shell architectures on the basis of ZIF-type materials have been very limited in the literatures. "
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    ABSTRACT: A facile synthesis strategy for preparing Fe3O4@ZIF-8 magnetic core-shell microspheres has been successfully developed. The procedure involves first pre-treating the magnetic cores with an anionic polyelectrolyte to alter the surface charge of the particles and adsorb Zn2+ cations to initiate nucleation and then growing a thin layer of ZIF-8 to form a highly reactive, magnetic core-shell microsphere (Fe3O4@ZIF-8). The characterization by various techniques indicates that ZIF-8 shell is continuous and has an average thickness of around 100 nm. The Fe3O4@ZIF-8 microspheres as catalysts could be easily filled into a capillary microreactor with the help of an external magnetic field. The microreactor demonstrates excellent catalytic activity at a shorter residence time for Knoevenagel condensation reaction of benzaldehyde and ethyl cyanoacetate.
    Chemical Engineering Journal 07/2013; 228:398-404. DOI:10.1016/j.cej.2013.05.020 · 4.32 Impact Factor
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