Isotopic effect on the non-isothermal dehydrogenation kinetics of lithium alanates

The isotopic effect on the dehydrogenation kinetics of lithium alanate has been studied. The desorption of hydrogen/deuterium of LiAlH4/LiAlD4 occurs in two steps below 300 °C. The deuterium desorption temperature of LiAlD4 was found to be marginally higher for both the steps as compared to hydrogen desorption of LiAlH4. The apparent activation energy of hydrogen/deuterium desorption was evaluated and found to be in the order of EaLiAlH4>EaLiAlD4. The higher desorption temperature of LiAlD4 has been explained on the basis the zero point energy per unit H/D atom of the alanates. The results indicate the normal isotopic effect of lithium alanate, which could be extended for the tritium.