2009 NSF Inorganic Workshop
Park City, UT
In the synthesis of hydrogen storage materials, the current frontier is to produce materials with nanoscopic control. One chief challenge is to utilize molecular precursors and convert them into solid state structures with that desired purpose. Conventional routes of laser ablation/matrix deposition chemistry, high-temperature chemistry, and aqueous solution chemistry need to be diversified with softer routes. This poster describes such a new route that produces potentially bare metal atoms in solution that coalesce to form particles down to the nanoscale and that will be much more efficient in reactions with hydrogen at or near room temperature and pressure. As a first step to reaching the above goal we have shown that nanoscopic iron results from the known species, [FeH6][MgX(THF)2]4 (X = Cl & Br), via solution comproportionation with FeX2.1 The expansion of this chemistry to other first row transition metals is supported by the preparation of [CoH5][MgX(THF)2]4, for which we show evidence. Our homoleptic species and complexes such as, [WH4(H2)4], prepared in hydrogen matrix encompass analogous cyanide complexes.2 The thermodynamics of the Kubas-type complexes would have an ideal binding energy (10-40 kJ/mol) that would permit reversible hydrogen storage at near ambient conditions.3 Kubas hydrides, e.g. [MHx(H2)y] (y > 2; M = first row TM) species, would appear to meet DOE targets. 1 Linn, D. E., Jr.; Guo, Y.; Cramer, S. P. Reactions of hexahydridoferrate(4-) and iron(II) that produce iron particles. Inorg. Chim. Acta, 2008, 361, 1552-1554. 2 Wang, X.; Andrews,L; Infante, I.; Gagliardi, L. Infrared spectra of the WH4(H2)4 complex in solid hydrogen. J. Am. Chem. Soc. 2007, 130, 1972-1978. 3 Kubas, G. Fundamentals of H2 Binding and Reactivity on Transition Metals Underlying Hydrogenase Function and H2 Production and Storage. Chem. Rev. 2007, 107, 4152-4205.
Hydrogen storage, hydrides, nanoscopic metals
Chemistry | Inorganic Chemistry | Materials Chemistry
Donald Edward Linn Jr (2009).
The Soluble Hexahydridoferrate and Pentahydridocobaltate: Comproportionation to Produce Nanoscopic "Bare" Metals. Presented at 2009 NSF Inorganic Workshop, Park City, UT.