Doping effect of Nb species on hydrogen desorption properties of AlH3

Hydrogen desorption properties of α-AlH3 doped with Nb species (Nb, Nb2O5 and NbF5) were investigated. Doping Nb species improved the desorption properties of AlH3. In particular, 1 mol% NbF5-doped AlH3 showed the lowest onset desorption temperature at 60 °C. Compared with Nb- or Nb2O5-doped AlH3, the fine distribution of dopant was successfully achieved in NbF5-doped AlH3. The apparent activation energy for hydrogen desorption of AlH3 was slightly decreased with the dopant of NbF5. The improvement of desorption properties might be due to the finely dispersed Nb and/or AlF3, which are formed by the reaction between NbF5 and AlH3 (surface Al2O3).