Study on catalytic effect and mechanism of MOF (MOF = ZIF-8, ZIF-67, MOF-74) on hydrogen storage properties of magnesium

• Published in: International journal of hydrogen energy 2019-11, Vol.44 (54), p.28863-28873
• Main Authors: Wang, Yongqing, Lan, Zhiqiang, Huang, Xiantun, Liu, Haizhen, Guo, Jin
• Format: Article
• Language: English
• Subjects: Hydrogen storage property; Magnesium; Metal-organic framework
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2019.09.110

Using a deposition-reduction method, Mg/MOF nanocomposites were prepared as composites of Mg and metal-organic framework materials (MOFs = ZIF-8, ZIF-67 and MOF-74). The addition of MOFs can enhance the hydrogen storage properties of Mg. For example, within 5000 s, 0.6 wt%, 1.2 wt%, 2.7 wt%, 3.7 wt% of hydrogen were released from Mg, Mg/MOF-74, Mg/ZIF-8, Mg/ZIF-67, respectively. Activation energy values of 198.9 kJ mol−1 H2, 161.7 kJ mol−1 H2, 192.1 kJ mol−1 H2 were determined for the Mg/ZIF-8, Mg/ZIF-67, Mg/MOF-74 hydrides, which are 6 kJ mol−1 H2, 43.2 kJ mol−1 H2, and 12.8 kJ mol−1 H2 lower than that of Mg hydride, respectively. Moreover, the cyclic stability characterizing Mg hydride was significantly improved when adding ZIF-67. The hydrogen storage capacity of the Mg/ZIF-67 nanocomposite remained unchanged, even after 100 cycles of hydrogenation/dehydrogenation. This excellent cyclic stability may have resulted from the core-shell structure of the Mg/ZIF-67 nanocomposite. [Display omitted] •Influence of MOFs on the hydrogen storage properties of Mg is investigated.•The excellent cyclic stability of Mg/ZIF-67 attributed to its core-shell structure.•The CoMg2 formed in Mg/ZIF-67 improve the hydrogen storage property of Mg.