Microstructure and Hydrogen Storage Properties of Melt‐Spun Mg 91 Y 3 Al 6 Alloy

Unraveling the Synergistic Catalytic Effects of TiO2 and Pr6O11 on Superior Dehydrogenation Performances of α-AlH3

The pivotal steps for the practical application of dehydrogenation of aluminum hydride (AlH₃) have been to decrease the temperature and increase the content of AlH₃. Herein, the initial dehydrogenation temperature of AlH₃ decreased to 43 °C with the amount of released hydrogen of 8.3 wt % via introducing TiO₂ and Pr₆O₁₁ with synergistic catalysis effects, and its apparent activation energy of the dehydrogenation reaction decreased to 56.1 kJ mol^-1, which is 52% lower than that of pure AlH₃. These differences in performances of the samples are further evaluated by determining the electron density of Al-H bonds during dehydrogenation. The multiple valence state conversions of TiO₂ and Pr₆O₁₁ promoted the electron transfer of H in AlH₃, and a novel dehydrogenation pathway of PrH_2.37 formed simultaneously, which could accelerate the breakage of Al-H bonds. The density functional theory calculations further exhibit that there are fewer electrons around H in AlH₃ and the Al-H bond energy is weaker at the atomic levels, which is more conducive to the release of hydrogen. A higher hydrogen storage capacity and a lower dehydrogenation temperature make AlH₃ one of the most promising hydrogen source media for mobile applications.