High-throughput synthesis of zeolitic imidazolate frameworks and application to CO2 capture.

Center for Reticular Chemistry at California NanoSystems Institute, Department of Chemistry and Biochemistry, University of California at Los Angeles, 607 East Charles E. Young Drive, Los Angeles, CA 90095, USA.
Science (Impact Factor: 31.48). 03/2008; 319(5865):939-43. DOI: 10.1126/science.1152516
Source: PubMed

ABSTRACT A high-throughput protocol was developed for the synthesis of zeolitic imidazolate frameworks (ZIFs). Twenty-five different ZIF crystals were synthesized from only 9600 microreactions of either zinc(II)/cobalt(II) and imidazolate/imidazolate-type linkers. All of the ZIF structures have tetrahedral frameworks: 10 of which have two different links (heterolinks), 16 of which are previously unobserved compositions and structures, and 5 of which have topologies as yet unobserved in zeolites. Members of a selection of these ZIFs (termed ZIF-68, ZIF-69, and ZIF-70) have high thermal stability (up to 390 degrees C) and chemical stability in refluxing organic and aqueous media. Their frameworks have high porosity (with surface areas up to 1970 square meters per gram), and they exhibit unusual selectivity for CO2 capture from CO2/CO mixtures and extraordinary capacity for storing CO2: 1 liter of ZIF-69 can hold approximately 83 liters of CO2 at 273 kelvin under ambient pressure.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A good material for CO2 capture should possess some specific properties: (i) a large effective surface area with good adsorption capacity, (ii) selectivity for CO2, (iii) regeneration capacity with minimum energy input, allowing reutilization of the material for CO2 adsorption, and (iv) low cost and high environmental friendliness. Smectite clays are layered nanoporous materials that may be good candidates in this context. Here we report experiments which show that gaseous CO2 intercalates into the interlayer nano-space of smectite clay (synthetic fluorohectorite) at conditions close to ambient. The rate of intercalation, as well as the retention ability of CO2 was found to be strongly dependent on the type of the interlayer cation, which in the present case is Li(+), Na(+) or Ni(2+). Interestingly, we observe that the smectite Li-fluorohectorite is able to retain CO2 up to a temperature of 35°C at ambient pressure, and that the captured CO2 can be released by heating above this temperature. Our estimates indicate that smectite clays, even with the standard cations analyzed here, can capture an amount of CO2 comparable to other materials studied in this context.
    Scientific Reports 03/2015; 5:8775. DOI:10.1038/srep08775 · 5.08 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this article, two new charge equilibration methods for estimating atomic partial charges are outlined. These methods are based on expanding the Taylor series used to estimate the ionization energy of each atom about either the formal or atomic charge, allowing for accurate charge estimation in both covalent and ionic materials. A new treatment of hydrogen atoms based on molecular hydrogen is also introduced. To demonstrate their general applicability, these new methods have been applied to the simulation of CO2 adsorption in metalorganic frameworks. Comparisons with other charge equilibration methods and density functional theory (DFT) calculations show that, of the rapid charge-assigning methods, the algorithm based on atomic ionization best replicates the DFT electrostatic potential and provides the most accurate estimation of CO2 adsorption.
    The Journal of Physical Chemistry C 01/2015; 119(1):456-466. DOI:10.1021/jp510415h · 4.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: High qualify ZIF-8 membranes of about 2.5 mu m in thickness were prepared on alpha-Al2O3 support by secondary growth synthesis in water solution. Single He, H-2, CO2, N-2, CH4, C3H6 and C3H8 permeation data for the ZIF-8 membranes were measured and analyzed by a permeation model to obtain diffusivity values of these gases in ZIF-8 crystals. The diffusivity values obtained from gas pet meance tests were in the range of 1 x 10(-6)- X 10(-4) cm(2)/s. Diffusivity value decreases with increasing molecular size in the order He > H2> CO2, > N-2> CH4. Gas permeance for the above light gases remains constant while for C3H6 and C3H8 pet meance decreased with increasing pressure due to the specific pressure dependency of the adsorption isotherm respective to each gas. The determined diffusivity for propylene and propane is 1.25 x 10(-8) cm(2)is and 3.99 x 10(-10) cm2/s with activation energy for diffusion of 12.7 kJimol and 38.8 kilmol respectively. With equal-molar binary feed, the ZIF-8 membranes exhibit consistent C3H6/C3H8 selectivity of about 30 and C3H6 permeance of 11 x 10(-8) mol/m(2)sPa. A month long stability test shows stable gas permeance and separation performance of the ZIF-8 membranes in both atmospheric conditions and C3H6/C3H8 mixture stream.
    Journal of Membrane Science 02/2014; 451:85-93. DOI:10.1016/j.memsci.2013.09.029 · 4.91 Impact Factor

Full-text (2 Sources)

Available from
Jun 4, 2014