The Effects of Chemical Additives on the Induction Phase in Solid-State Thermal Decomposition of Ammonia Borane
The solid-state decomposition of ammonia borane (AB) alone and in the presence of chemical additives was investigated by a series of experimental methods to develop an approach for reducing the induction period for hydrogen release. Gas chromatography techniques were used to measure the yield of hydrogen as a function of time under isothermal conditions between 70 and 90 °C, and the polyaminoborane (PAB) products produced from hydrogen loss from AB show significant cross linking by 11B NMR spectroscopy. Raman microscopy was used to follow the transformation of crystalline AB to amorphous AB with the subsequent formation of the diammoniate of diborane (DADB). A gas burette was used to monitor the time-dependent release of hydrogen from AB in the presence of chemical additives. The combination of these approaches provides insight into the mechanism of hydrogen release from solid AB. The release of molecular hydrogen is described by a process involving sequential induction (disruption of dihydrogen bonds), nucleation (formation of DADB), and growth (hydrogen release through dehydrocoupling). Addition of DADB or ammonium chloride to neat AB significantly reduces the induction time for hydrogen release. The authors wish to acknowledge support from the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy. This work was performed as part of the Center of Excellence in Chemical Hydrogen Storage and in collaboration with the International Partnership for the Hydrogen Economy. Pacific Northwest National Laboratory is operated for the U.S. Department of Energy by Battelle.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 952401
- Report Number(s):
- PNNL-SA-60433; EB4202000
- Journal Information:
- Chemistry of Materials, 20(16):5332-5336, Journal Name: Chemistry of Materials, 20(16):5332-5336 Journal Issue: 16 Vol. 20; ISSN CMATEX; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ADDITIVES
AMMONIA
AMMONIUM CHLORIDES
BORANES
CROSS-LINKING
DEHYDROGENATION
DIAMMONIATE
DIBORANE
DIMER
ENERGY EFFICIENCY
GAS CHROMATOGRAPHY
H3NBH3
HYDROGEN
HYDROGEN STORAGE
HYDROGEN STORAGE MATERIAL
INDUCTION
ION
MICROSCOPY
MONITORS
NUCLEATION
PYROLYSIS
RELEASE
SPECTROSCOPY
TRANSFORMATIONS
ammonia borane
hydrogen economy
hydrogen release