Ji Liang, Zhang Liuting, Yang Xinglin, Zhu Xinqiao, Chen Lixin
School of Energy and Power, Jiangsu University of Science and Technology, Zhenjiang 212003, China.
Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621999, China.
Dalton Trans. 2020 Apr 1;49(13):4146-4154. doi: 10.1039/d0dt00230e.
Magnesium hydride (MgH2) has been considered as a promising hydrogen storage material for buildings that are powered by hydrogen energy, but its practical application is hampered by poor kinetics and unstable thermodynamics. Herein, we describe a feasible method for preparing FeNi nanoparticles dispersed on reduced graphene oxide nanosheets (FeNi/rGO), and we confirmed that excellent catalytic effects increased the hydrogen storage performance of MgH2. 5 wt% FeNi/rGO-modified MgH2 began to release hydrogen at 230 °C and liberated 6.5 wt% H2 within 10 min at 300 °C. As for the hydrogenation process, the dehydrogenated sample absorbed 5.4 wt% H2 within 20 min at 125 °C under a hydrogen pressure of 32 bar. More importantly, a hydrogen capacity of 6.9 wt% was maintained after 50 cycles without compromising the kinetics during each cycle. A unique catalytic mechanism promoted synergetic effects between the in situ-formed Mg2Ni/Mg2NiH4, Fe, and rGO that efficiently promoted hydrogen dissociation and diffusion along the Mg/MgH2 interface, anchored the catalyst, and prevented MgH2 from aggregation and growth.
氢化镁（MgH₂）被认为是一种很有前景的储氢材料，可用于由氢能驱动的建筑物，但由于其动力学性能差和热力学不稳定，其实际应用受到阻碍。在此，我们描述了一种制备分散在还原氧化石墨烯纳米片上的FeNi纳米颗粒（FeNi/rGO）的可行方法，并证实了优异的催化效果提高了MgH₂的储氢性能。5 wt% FeNi/rGO改性的MgH₂在230℃开始释放氢气，并在300℃下10分钟内释放出6.5 wt%的H₂。至于氢化过程，脱氢后的样品在125℃、32 bar氢气压力下20分钟内吸收了5.4 wt%的H₂。更重要的是，在50次循环后仍保持6.9 wt%的储氢容量，且每次循环的动力学性能不受影响。一种独特的催化机制促进了原位形成的Mg₂Ni/Mg₂NiH₄、Fe和rGO之间的协同效应，有效地促进了氢沿着Mg/MgH₂界面的解离和扩散，并固定了催化剂，防止了MgH₂的聚集和生长。
