In situ X-ray diffraction measurement of the hydrogenation and dehydrogenation of aluminum and characterization of the recovered AlH3

Pristine aluminum was hydrogenated to form AlH₃ at 8.9 GPa and 600 °C. The cyclic formation and decomposition of the hydride were measured by in situ synchrotron X-ray diffraction measurement. AlH₃ synthesized under high pressure and temperature was recovered at ambient conditions. The recovered AlH₃ was characterized by conventional powder X-ray diffraction measurement and Raman spectroscopy. The results of the characterization were consistent with that obtained for chemically prepared AlH₃ and indicated that single phase α-AlH₃ was obtained.