Argonne National Laboratory
Chemical Sciences and Engineering Division Seminar
Speaker: Karen L. Mulfort
Department of Chemistry
Northwestern University
Title: Metal-Organic Architectures for Energy
Storage and Conversion
Date: Thursday, March 6, 2008
Time: 10:00 a.m.
Place: Conference Room J-183 (Building 200)
Host: David Tiede
Abstract: Metal-organic architectures are emerging as particularly attractive host-guest materials for chemical energy storage and conversion. Chemical functionality, cavity size, and shape can be readily tuned by manipulating the organic moieties within these hybrid materials. With this
ability to impart a high level of control over the final construct, these materials have the potential to revolutionize fields such as solar energy
harvesting and conversion, size-selection and enantioselective catalysis, and fuels storage.
To specifically address hydrogen storage concerns, we have developed a new class of mixed-ligand metal-organic frameworks (MOFs) of the
general formula Zn2(dicarboxylate)2(dipyridyl).1 Several of these materials can be chemically reduced in the solid state by common reductants
such as lithium naphthalenide or through direct contact with lithium metal. One structure in particular exhibits striking hysteresis in the N2
adsorption isotherm, suggesting dynamic framework behavior of the reduced material that is not observed in the neutral MOF.2
The reduced framework exhibits significantly enhanced H2 uptake and isosteric heat of adsorption. Notably, the striking increase in H2
uptake cannot be solely attributed to H2-Li+ interactions, and is most likely augmented by increased ligand polarizability and framework
displacement effects. Recently, this method has been generalized to new framework materials as well as other alkali metal cations.
(1) Ma, B. Q.; Mulfort, K. L.; Hupp, J. T. Inorg. Chem. 2005, 44, 4912-4914.
(2) Mulfort, K. L.; Hupp, J. T. J. Am. Chem. Soc. 2007, 129, 9604-9605.