Investigation of the Dehydrogenation Reaction Pathway of Ca(BH_4)_2 and Reversibility of Intermediate Phases
Abstract
The dehydrogenation reaction pathway of Ca(BH_4)_2 has been investigated under an isobaric condition of 1 bar of hydrogen. β-Ca(BH_4)_2 gradually transforms into the (XRD invisible) amorphous phase at the initial stage. Upon further heating, it decomposes into CaB_2H_x or CaB_(12)H_(12), indicating that there is a subtle competition between two different dehydrogenation routes: (i) Ca(BH_4)_2 → amorphous phase → CaB_2H_x + (4 – x)/2H_2 → 2/3CaH_2 + 1/3CaB_6 + 10/3H_2 and (ii) Ca(BH_4)_2 → amorphous phase → 1/6CaB_(12)H_(12) + 5/6CaH_2 + 13/6H_2. It has also been concluded that CaB_2H_x as well as the CaB_6 + CaH_2 mixture can be rehydrogenated at 330 °C under 90 bar of hydrogen without any catalytic additive, whereas CaB_(12)H_(12) hardly rehydrogenated under the same conditions.
Additional Information
© 2012 American Chemical Society. Received: November 7, 2011 Revised: January 3, 2012. Publication Date (Web): January 9, 2012. This work has been sponsored by the Hydrogen Energy R&D Center, one of the 21st Century Frontier R&D Programs funded by the Ministry of Education, Science and Technology of Korea. The NMR facility at Caltech was supported by the National Science Foundation (NSF) under Grant Number 9724240 and partially supported by the MRSEC Program of the NSF under Award Number DMR-520565. The authors gratefully acknowledge the support by Dr. Ik Jae Lee and Dr. Keun Hwa Chae at the KIST-PAL beamline for the in situ synchrotron XRD measurements. Y.K. and H.N.H acknowledged the support by National Research Foundation of Korea grant funded by the Ministry of Education, Science and Technology (2010-0018936).Additional details
- Eprint ID
- 29950
- Resolver ID
- CaltechAUTHORS:20120403-085929855
- Hydrogen Energy R&D Center
- DMR-9724240
- NSF
- DMR-0520565
- NSF
- National Research Foundation of Korea
- 2010-0018936
- Ministry of Education, Science and Technology (Korea)
- Created
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2012-04-03Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field