Energy Storage in Nanoporous MetalOrganic Framework Materials Cameron

Energy Storage in Nanoporous Metal-Organic Framework Materials Cameron J. Kepert, School of Chemistry, University of Sydney The question of how best to store hydrogen gas has arisen in parallel with the development of an important new class of materials that shows outstanding promise in this area, namely, metal-organic frameworks. These materials have recently exceeded the 6. 5 wt% 2010 target for reversible hydrogen sorption, with maximal loading occurring under comparatively extreme pressures (high) and/or temperatures (low). In targeting both high gravimetric and volumetric hydrogen uptakes in these systems at less extreme conditions our synthetic efforts have been driven by a number of considerations: 1) the achievement of high dihydrogen physisorption binding enthalpies through the generation of high-energy surfaces; 2) the achievement of both structural robustness and high surface areas through the use of large, rigid molecular tectons; 3) the achievement of low -density framework architectures through the use of relatively light elements. Structural and physical characterizations of these materials have utilized a barrage of techniques that include X-ray and neutron scattering/diffraction, gas sorption measurement, vibrational spectroscopy, and theoretical simulation. Notable recent results include the following: • The synthesis and characterization of a range of new porous framework materials • Post-synthetic surface modification of existing metal-organic framework phases to increase the physisorptive dihydrogen binding enthalpy • Detailed characterization of hydrogen sorption, including investigation of the Cu…H 2 interaction, within [Cu 3(btc)2] (btc = 1, 3, 5 -benzenetricarboxylate) through powder neutron diffraction, inelastic neutron scattering, and DFT modeling (see plots) • Structural characterization of the iterative sorption of D 2 into a range of metal-organic framework systems by powder neutron diffraction (see fig); points of particular note here include the observation of short M…D 2 interactions and the formation of close-packed D 2 monolayers and clusters within large and small pores.