Synthesis of highly stable Ni nanoparticles via electrostatic self‐assembly for enhanced hydrogen storage of MgH <sub>2</sub>
Qinke Tang, Jiangchuan Liu, Rui Shi, Yunfeng Zhu, Ji‐Guang Zhang, Yana Liu, Jun Wang, Yao Zhang, Xiaohui Hu, Zhibin Liu, Liquan Li
Abstract
Abstract Magnesium‐based hydrides have been widely recognized as an appropriate choice for solid‐state hydrogen storage. However, its undesirable thermodynamics and sluggish hydrogenation/dehydrogenation kinetics are major bottlenecks for its application. Herein, a highly stable and highly dispersed Ni‐based catalyst (Ni/Al 2 O 3 /GN) was fabricated to promote the hydrogen storage performance of MgH 2 via the electrostatic effect of NiAl‐LDH/GN precursor with a co‐calcination reduction process. MgH 2 ‐5 wt% Ni/Al 2 O 3 /GN exhibits excellent hydrogen storage performance, releasing about 5.7 wt% hydrogen in 3500 s at 250 °C, and can reach a saturation hydrogen absorption of about 6.15 wt% in 3000 s at 100 °C. Furthermore, it also shows low dehydrogenation apparent activation energy of 89.1 and 118.2 kJ·mol −1 . Impressively, the catalyst ensures the stability of both the physical phase and structure during ball milling and cycling process. The role of each phase in Ni/Al 2 O 3 /GN on the hydrogen storage performance of MgH 2 was also discussed through experiments and theoretical calculation, and the synergistic catalytic mechanism of Ni/Al 2 O 3 /GN was clearly elaborated. This work provides a unique perspective for the preparation of highly stable and highly dispersible catalysts.