Metal Hydride Confinement in Functionalized Porous Hosts: Tuning Hydrogen Release Thermodynamics and Kinetics
Final Report Abstract
In summary, during my Postdoc project at Sandia National Laboratories, I had the chance to work on several highly motivating and interesting topics. On the one hand, I learned a lot about Metal Hydrides and their incorporation into porous hosts, and on the other hand I was able to use state of the art synchrotron techniques and adsorption measurements to determine thermal expansion and adsorption properties of metal-organic frameworks. I was able to get some detailed insights into the dehydrogenation processes in nanoscaled metal-hydrides, via multiple methods, including computational methods, in-situ NMR, X-ray adsorption spectroscopy and thermal analysis. Through our innovative approach of anchoring Mg(BH4)2 to the chelating groups of bipyridine, we achieved a new form of nanoscaling of hydrides which hasn’t been reported yet. The coordination of the Mg(BH4)2 triggered release of clean hydrogen at around 120 °C, which is substantially lower than for pristine Mg(BH4)2. Density Functional Theory calculations (nudged electron band technique), verified that the coordination substantially lowered the activation barrier towards hydrogen release. These results will help to design even more advanced hydrogen storage materials. Secondly, I was able to learn a lot about the effect of linker functionalization on the thermal expansion behavior of metal-organic frameworks. A series of MOFs with tunable thermal expansion along the a/b plane from positive to negative was prepared, paving the way for new zero-thermal expansion devices.
Publications
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(2020) A Mechanistic Analysis of Phase Evolution and Hydrogen Storage Behavior in Nanocrystalline Mg(BH4)2 within Reduced Graphene Oxide. ACS nano 14 (2) 1745–1756
Jeong, Sohee; Heo, Tae Wook; Oktawiec, Julia; Shi, Rongpei; Kang, ShinYoung; White, James L.; Schneemann, Andreas; Zaia, Edmond W.; Wan, Liwen F.; Ray, Keith G.; Liu, Yi-Sheng; Stavila, Vitalie; Guo, Jinghua; Long, Jeffrey R.; Wood, Brandon C.; Urban, Jef
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“Nanostructured Metal Hydrides for Hydrogen Storage”. Chem. Rev., 2018, 118, 10775
A. Schneemann, J. L. White, S. Kang, S. Jeong, L. F. Wan, E. S. Cho, T. W. Heo, D. Prendergast, J. J. Urban, B. C. Wood, M. D. Allendorf, and V. Stavila
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“Negative thermal expansion design strategies in a diverse series of metal-organic frameworks”. Adv. Funct. Mater. 2019, 29, 1904669
N. C. Burtch, S. J. Baxter, J. Heinen, A. Bird, A. Schneemann, D. Dubbeldam, and A. P. Wilkinson
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“Tuning Thermal Expansion in Metal-Organic Frameworks using a Mixed Linker Solid Solution Approach”. J. Am. Chem. Soc. 2019, 141, 12849
S. J. Baxter, A. Schneemann, A. Ready, P. Wijeratne, A. P. Wilkinson, N. C. Burtch
