Enhanced hydrogen storage kinetics of an Mg-Pr-Al composite by in situ formed Pr3Al11 nanoparticles
Enhanced hydrogen storage kinetics of an Mg-Pr-Al composite by in situ formed Pr3Al11 nanoparticles
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原位形成的 Pr3Al11 纳米颗粒增强 Mg-Pr-Al 复合材料的储氢动力学
DOI：
10.1039/c9dt01214a
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发表时间：
2019
影响因子：
4
通讯作者：
Zhang Qingan
中科院分区：
文献类型：
--
作者：
Zhou Caiqin;Li Can;Li Yongtao;Zhang Qingan
缓慢的吸氢动力学是氢氧化镁实用化面临的挑战之一。为提高吸氢动力学性能，采用球磨法制备了14MgH2+Pr+Al复合粉末。在Mg-Pr-Al复合材料的加氢和脱氢过程中，伴随着氢气的吸附和脱附，发生了两个可逆的副反应，即2PrH_2+H_2=2PrH_3和Mg_17Al_(12+17H_2)=17_mH_2+12Al。活化后的Mg-Pr-Al复合材料中原位生成的Pr3Al11相在进一步的氢吸附和放氢过程中是稳定的，这对镁微晶的生长起到了抑制作用。因此，Mg-Pr-Al复合材料吸氢动力学的改善归因于Pr3Al11对微晶生长的抑制作用和PrH3/PrH2对吸氢的催化作用。这些发现为开发具有优异储氢性能的新型镁基材料提供了重要的指导。
Slow hydrogen sorption kinetics is one of the challenges facing practical applications of MgH2. To improve the hydrogen sorption kinetics, an Mg–Pr–Al composite is prepared by ball milling of a 14MgH2 + Pr + Al powder mixture. During hydrogenation and dehydrogenation processes of the Mg–Pr–Al composite, two reversible side reactions, i.e. 2PrH2 + H2 = 2PrH3 and Mg17Al12 + 17H2 = 17MgH2 + 12Al, occur accompanying hydrogen adsorption and desorption of the Mg–H2 system. The in situ formed Pr3Al11 phase in the activated Mg–Pr–Al composite is stable during further hydrogen adsorption and desorption processes, which plays a role in inhibiting growth of Mg crystallites. Hence, the improvement of hydrogen sorption kinetics for the Mg–Pr–Al composite is ascribed to the inhibiting role of Pr3Al11 in crystallite growth as well as the catalytic effect of PrH3/PrH2 on hydrogen sorption. These findings provide an important guidance for developing new Mg-based materials with superior hydrogen storage properties.