Date of Award
Master of Science
Pressure-induced structural transformations of two potential hydrogen storage materials, i.e., ammonia borane (NH3-BH3) and calcium borohydride [Ca(BH4)2] were investigated in diamond anvil cells by Raman and IR spectroscopy at ambient temperature up to 14 GPa and 10 GPa, respectively. By monitoring the profile evolutions of Raman and IR modes as well as changes of pressure coefficients, ammonia borane and calcium borohydride were found to undergo several phase transitions upon compression. Decompression measurements suggest those pressure-induced phase transitions were reversible for both materials. Structures of the new phases at different pressure ranges were analyzed based on our Raman and IR data. Our work on ammonia borane complements previous high pressure study on this material by providing new information on the structures and stabilities, while that on calcium borohydride constitutes the first high-pressure experimental study.
Xie, Shuntai, "In situ High-pressure Study of Hydrogen Storage Materials by Vibrational Spectroscopy" (2009). Digitized Theses. 4206.