Dehydrogenation process of AlH3 observed by TEM

Dehydrogenation processes of α- and γ-AlH3 were investigated by in situ transmission electron microscopy observations. The relationship between Al2O3 thickness and dehydrogenation kinetics was also clarified. The initial shape of α-AlH3 particle was cubic and that of γ-AlH3 particle was rod-shaped. The process of γ-AlH3 was quite similar with α-AlH3. The precipitation and growth of Al was observed in both processes. The dehydrogenation kinetics did not depend on Al2O3 thickness. It was found that milling effect on the dehydrogenation kinetics was larger than doping effect. The dehydrogenation process was discussed in terms of both microscopic and kinetic studies.

► The initial shape of α-AlH3 particle is cubic and that of γ-AlH3 is rod-shaped.
► Dehydrogenation kinetics does not depend on Al2O3 thickness in the 4.6–7.8 nm range.
► Milling effect on dehydrogenation kinetics will be larger than doping effect.