Discovery of Highly Advanced Materials

CENCEA is currently pursuing the development of the next generation of porous, crystalline materials: metal-organic frameworks (MOFs), covalent-organic frameworks (COFs), and zeolitic imidazolate frameworks (ZIFs). Through this pursuit, CENCEA researchers are putting the principles of reticular chemistry to work, in which MOFs, COFs, and ZIFs are being designed in order to achieve solutions for outstanding challenges in renewable and clean energy. One of the latest discoveries made through the CENCEA partnership was the realization of a woven framework – a material previously unseen by the world (pictured to the right).

Research topics:

  • Metal-organic frameworks (MOFs): stitching together transition metal and main group ions with organic molecular building units to form extended, crystalline frameworks
  • Multivariate (MTV) MOFs: to assemble MOF structures from links with different functional groups whose orientation, number, relative position, and ratio along the backbone can be controlled by virtue of the unchanged length of the link and its unaltered connectivity
  • Covalent organic frameworksassembly of organic building units held together by strong covalent bonds and light elements
  • Woven frameworks: the interlacing of 1D units to make 2D and 3D structures, which have many more degrees of freedom for enormous spatial deviations, by each of the threads, to take place independently and still preserve the underlying topology. Such freedom may enable reversible control over the mechanical properties of materials.
  • Heterogeneity within order: creating, by design, more complex MOF structures by either mixing of organic linkers within the MOF backbone; b) mixing of the metal-containing secondary building units (SBUs); c) mixing of both the SBUs and organic linkers within the same MOF backbone; d) mixing of functional groups along the backbone; e) MOFs with random and ordered defects; f) attaching MOFs to functional surfaces; g) combining inorganic nanocrystals and MOFs; or  h) MOFs with heterogeneous pores.

Recent representative publications:

  • Principles of Designing Extra-Large Pore Openings and Cages in Zeolitic Imidazolate Frameworks, J. Yang, Y. Zhang, Q. Liu, C. A. Trickett, E. Gutierrez-Puebla, M. Á. Monge, H. Cong, A. Aldossary, H. Deng, O. M. Yaghi J. Am. Chem. Soc.2017, DOI:10.1021/jacs.7b02272
  • Weaving of Organic Threads into a Crystalline Covalent Organic Framework, Y. Liu, Y. Ma, Y. Zhao, X. Sun, F. Gándara, H. Furukawa, Z. Liu, H. Zhu, C. Zhu, K. Suenaga, P. Oleynikov, A. S. Alshammari, X. Zhang, O. Terasaki, O. M. Yaghi, Science2016351, 365.
  • High Methane Storage Working Capacity in Metal-Organic Frameworks with Acrylate Links, J. Jiang, H. Furukawa, Y.-B. Zhang, O. M. Yaghi, J. Am. Chem. Soc.2016138, 10244.
  • Nanoporous Transparent MOF Glasses with Accessible Internal Surface, Y. Zhao, S. Lee, N. Becknell, O. M. Yaghi, C. A. Angell, J. Am. Chem. Soc.2016138, 10818.
  • Coordinative Alignment of Molecules in Chiral Metal-Organic Frameworks, S. Lee, E. Kapustin, O. M. Yaghi, Science2016353, 808.
  • Structures of Metal–Organic Frameworks with Rod Secondary Building Units, A. Schoedel, M. Li, D. Li, M. O’Keeffe, O. M. Yaghi, Chem. Rev.2016116, 12466.
  • "Heterogeneity within Order" in Metal-Organic Frameworks, H. Furukawa, U. Muller, O. M. Yaghi, Angew. Chem. Int. Ed.201554, 3417.

Carbon Dioxide Capture and Conversion

Carbon dioxide is typically considered a waste product since it is commonly released as a result of combustion, and its production is ever-increasing as the world’s energy demands grow. Due to the threat of climate change, substantial efforts have been made into CO2 capture and storage. The next step forward is the conversion of CO2 into value-added products such as formic acid and methanol, and is being investigated as a highly desirable use of such an abundant starting material. An ideal material for this application would be (i) reusable without loss of activity, (ii) be employed in a flow-type system rather than by batch reaction, (iii) be selective and high-yielding for the desired product, and (iv) could be used under mild conditions. However, while progress has been made, such a material has not yet been commercially developed.

Metal-organic frameworks (MOFs), with their porosity and highly functionalizable nature, are hugely promising for such applications since these materials can be designed with the desired pore environment and size to perform heterogeneous catalysis. MOFs can be used as an environment to concentrate CO2 and catalyze its conversion. Thus, CENCEA is currently exploring the synthesis of new heterogeneous MOF platforms, which can simultaneously capture and convert CO2.

Research topics:

  • Photocatalytic MOFs: a number of approaches are being used, including employing the SBU, the organic linker, grafting a photocatalytically active site onto the linker, some combination of these as the source of active sites, or fabricating composite materials with nanoparticles to create a MOF photocatalyst
  • Electrocatalytic COFs: combining the advantages of using molecular catalysts as building blocks for the construction of covalent organic frameworks, which possess many desirable properties for use as electrocatalysts, such as high charge carrier mobility, stability to water, and the possibility to functionalize the organic backbone of the structure. Furthermore, by incoporating molecular catalytic units into the backbone of an extended COF framework gives rise to catalysts that display desirable features of both – molecular and solid state catalysts
  • Noble metals embedded with MOFs: interfacing MOFs with other catalytically active metals because of their nanosized metal oxide secondary building units (SBUs) and tunability of their compositions; hence allowing us to investigate the effects of catalytic interface systematically
  • Heterogenization of homogeneous catalysts: designing an ideal material, which is reusable without loss of activity, employed in a flow-type system rather than by batch reaction, selective and high-yielding for the desired product, and can be used under mild conditions

Recent representative publications:

  • Plasmon-Enhanced Photocatalytic CO2 Conversion within Metal-Organic Frameworks Under Visible Light, K. M. Choi, D. Kim, B. Rungtaweevoranit, C. A. Trickett, J. T. D. Barmanbek, A. Alshammari, P. Yang, O. M. Yaghi, J. Am. Chem. Soc.2017139, 356.
  • Copper Nanocrystals Encapsulated in Zr-based Metal-Organic Frameworks for Highly Selective CO2 Hydrogenation to Methanol, B. Rungtaweevoranit, J. Baek, J. R. Araujo, B. S. Archanjo, K. M. Choi, O. M. Yaghi, G. A. Somorjai, Nano Lett.201616, 7645.
  • Metal-Organic Frameworks for Electrocatalytic Reduction of Carbon Dioxide, N. Kornienko, Y. Zhao, C. S. Kley, C. Zhu, D. Kim, S. Lin, C. J. Chang, O. M. Yaghi, P. Yang, JAmChemSoc., 2015137, 14129.
  • Mesoscopic Constructs of Ordered And Oriented Metal-Organic Frameworks on Plasmonic Silver Nanocrystals, Y. Zhao, N. Kornienko, Z. Liu, C. Zhu, S. Asahina, T.-R. Kuo, W. Bao, C. Xie, A. Hexemer, O. Terasaki, P. Yang, O. M. Yaghi, J. Am. Chem. Soc.2015137, 2199.

Storage and Transportation of Clean Fuels

The high global demand of energy is mainly provided through burning of fossil fuels (86%), generating thirty-five billion tons of carbon dioxide annually. Since this amount is predicted to significantly increase in the foreseeable future, clean energy applications have recently attracted enormous societal, political and scientific interest. In this context, robust, porous, crystalline materials such as MOFs or COFs have gained popularity since they show great potential in solving this problem according to their many promising applications. In particular, the storage of environmentally related gases, i.e. small molecules such as carbon dioxide, methane or hydrogen, or the conversion of chemicals into valuable commodities,represent aspiring new avenues for research and development. Current targets for the storage of energy carriers, as set by the U.S. Department of Energy are: hydrogen: 5.5 wt%; methane: 0.5 g g-1 (sorbent) at 298 K and 65 bar, volumetric working capacity of 315 cm3 (STP) cm-3. With this in hand, CENCEA has embarked on a research program to design, synthesize, and ultimately realize new materials that are capable of achieving and even surpassing these storage targets.

Research topics:

  • New highly porous MOFs, COFs, and ZIFs: targeting the design, synthesis, and realization of the next generation of highly porous, solid materials, whose surface areas are >3000 m2 g-1
  • Methane storage: MOFs, COFs, and ZIFs for methane storage and separation from natural gas as well as the use of methane-filled MOFs for automobile fueling. Targets are currently set at 200 v/v at 298 K and 35 bar
  • Hydrogen storage: developing new strategies to increase the hydrogen uptake capacity in MOFs, COFs, ZIFs, and their functionalized/derivative forms. Targets are currently set at 10 wt% uptake capacity at 77 K and 100 bar as well as 3 wt% at 298 K and 100 bar
  • Harvesting water from air: new materials are being created that capture water from air, even at very low relatively humidity, in order to provide clean drinking water in remote places where water is scarce.

Recent representative publications:

  • Water Harvesting from Air with Metal-Organic Frameworks Powered by Natural Sunlight, H. Kim, S. Yang, S. R. Rao, S. Narayanan, E. A. Kapustin, H. Furukawa, A. S. Umans, O. M. Yaghi, E. N. Wang Science, 2017, DOI:10.1126/science.aam8743
  • High Methane Storage Working Capacity in Metal-Organic Frameworks with Acrylate Links,J. Jiang, H. Furukawa, Y.-B. Zhang, O. M. Yaghi, J. Am. Chem. Soc.2016138, 10244.
  • The Role of Metal–Organic Frameworks in a Carbon-Neutral Energy Cycle, A. Schoedel, Z. Ji, O. M. Yaghi, Nature Energy20161, 16034.
  • Introduction of Functionality, Selection of Topology, and Enhancement of Gas Adsorption in Multivariate Metal-Organic Framework-177, Y.-B. Zhang, H. Furukawa, N. Ko, W. Nie, H. J. Park, S. Okajima, K. E. Cordova, H. Deng, J. Kim, O. M. Yaghi, J. Am. Chem. Soc.2015137, 2641.