Effect of additives on the thermolysis of ammonia borane

FUEL 164

David J. Heldebrant, david.heldebrant@pnl.gov1, Tom Autrey2, John C. Linehan, john.linehan@pnl.gov3, Donald M. Camaioni, donald.camaioni@pnl.gov1, Scot D. Rassat, sd.rassat@pnl.gov4, and Feng Zheng, feng.zheng@pnl.gov5. (1) Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, (2) Pacific Northwest National Laboratory, PNNL, Richland, WA 99354, (3) Fundamental Science Division, Pacific Northwest National Laboratory, P. O. Box 999 MSIN K2-57, Richland, WA 99352, (4) Environmental Technology Directorate, Pacific Northwest National Laboratory, P.O. Box 999, MS K6-28, Richland, WA 99352, (5) Energy & Efficiency Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN: K2-12, Richland, WA 99352
Ammonia borane (AB) is an attractive hydrogen storage material with high gravimetric and volumetric density of hydrogen. The thermolysis of solid ammonia borane follows sigmoidal kinetics with an “induction period” prior to rapid hydrogen release, generating a complex mixture of spent fuel products. We present evidence for the induction period involving isomerization of AB into the diammoniate of diborane (DADB). The induction period is substantially decreased with the addition of DADB. The induction period is also dependent on AB purity and temperature. Reducing the induction period and enhancing the rate of hydrogen release ultimately makes AB an attractive hydrogen storage material for fuel applications. This study profiles the mechanism of the thermolysis of AB, the effect of AB purity and the effect of chemical additives on the induction period and rates of dehydrogenation of AB.

PNNL is operated by Battelle for US DOE.

 

Hydrogen Storage and Fuel Cell Technology
1:10 PM-6:00 PM, Tuesday, August 21, 2007 Boston Park Plaza -- Cambridge Rm, Oral

Division of Fuel Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007