Nanoscaffold Mediates Hydrogen Release and the Reactivity of Ammonia Borane
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L. de Palacio P. Busquin Report from Europa Commission “Hydrogen Energy and Fuels Cells: A Vision for Our Future” http://europa.eu.int/comm/research/energy/nn/nn_rt/nn_rt_hlg/article_1146_en.htm.
Recent information can be found at:http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/freedomcar_targets_explanations.pdf.
M.Gutowski T.Autrey J.Linehan unpublished results.
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J. Baumann Dissertation Physikalisch‐chemische Untersuchungen zur Wasserstoffabgabe von BNH‐Verbindungen 2003 TU‐Bergakademie Freiberg Germany. The research group in Freiberg has been investigating NH3BH3as a hydrogen‐storage material.
Gutowski M., 2004, Prepr. Pap. Am. Chem. Soc. Div. Fuel Chem., 49, 275
Liang J., 2003, Prepr. Pap. Am. Chem. Soc. Div. Fuel Chem., 48, 281
The 800‐MHz solid‐state NMR spectrum is available as Supporting Information. Observed11B resonances: AB:SBA‐15 (one signal δ=−23 ppm) neat AB (four signals δ=−6 −12 −23 −37 ppm).
van 't Hoff equation: ln(peq/${p{{{\rm o}\hfill \atop {\rm eq}\hfill}}}$)=ΔH/RT−ΔS/R. The difference in hydrogen overpressure can be calculated from ΔΔHof H2loss from AB bulk and AB in the scaffold. Δln(peq/${p{{{\rm o}\hfill \atop {\rm eq}\hfill}}}$)=ΔΔH/RT−ΔΔS/R. ΔΔS=0 ΔΔH=20 kJ mol−1 thenpeq(AB)/peq(AB:SBA‐15)=4667. As ΔH≈0 in the scaffold the pressure required for H2uptake by the spent AB is the pressure required to overcome the entropy of formation of the gaseous H2. Reversibility processes will be addressed in a subsequent publication.