Liang Long, Wang Chunli, Ren Mingan, Li Shouliang, Wu Zhijian, Wang Limin, Liang Fei
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, CAS, Changchun 130022, China.
School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China.
ACS Appl Mater Interfaces. 2021 Jun 16;13(23):26998-27005. doi: 10.1021/acsami.1c04534. Epub 2021 Jun 2.
The pivotal steps for the practical application of dehydrogenation of aluminum hydride (AlH) have been to decrease the temperature and increase the content of AlH. Herein, the initial dehydrogenation temperature of AlH decreased to 43 °C with the amount of released hydrogen of 8.3 wt % via introducing TiO and PrO with synergistic catalysis effects, and its apparent activation energy of the dehydrogenation reaction decreased to 56.1 kJ mol, which is 52% lower than that of pure AlH. 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 TiO and PrO promoted the electron transfer of H in AlH, and a novel dehydrogenation pathway of PrH 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 AlH 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 AlH one of the most promising hydrogen source media for mobile applications.
氢化铝（AlH）实际应用的关键步骤是降低温度并提高AlH的含量。在此，通过引入具有协同催化作用的TiO和PrO，AlH的初始脱氢温度降至43°C，释氢量为8.3 wt%，其脱氢反应的表观活化能降至56.1 kJ/mol，比纯AlH低52%。通过测定脱氢过程中Al-H键的电子密度，进一步评估了样品性能的这些差异。TiO和PrO的多价态转变促进了AlH中H的电子转移，同时形成了一种新的PrH脱氢途径，可加速Al-H键的断裂。密度泛函理论计算进一步表明，在原子水平上，AlH中H周围的电子较少，Al-H键能较弱，这更有利于氢的释放。较高的储氢容量和较低的脱氢温度使AlH成为移动应用中最有前景的氢源介质之一。
