Improved Hydrogen Storage Performance of MgH2–LiAlH4 Composite by Addition of MnFe2O4

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• 作者：Qi Wan ; Ping Li ; Ziliang Li ; Fuqiang Zhai ; Xuanhui Qu ; Alex A. Volinsky
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：December 27, 2013
• 年：2013
• 卷：117
• 期：51
• 页码：26940-26947
• 全文大小：395K
• ISSN：1932-7455

文摘

The catalytic effects of MnFe₂O₄ nanoparticles on the hydrogen storage properties of MgH₂鈥揕iAlH₄, prepared by ball milling, are studied for the first time. The hydrogen storage properties and reaction mechanism are investigated by pressure鈥揷omposition鈥搕emperature (PCT), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The nonisothermal desorption results show that MgH₂鈥揕iAlH₄ + 5 mol % MnFe₂O₄ has a lower onset dehydrogenation temperature, 85, 50, and 40 掳C lower than these of ball-milled MgH₂鈥揕iAlH₄ sample for each stage in the dehydrogenation process. The isothermal dehydriding kinetics and isothermal rehydrogenation kinetics results indicate that adding MnFe₂O₄ to MgH₂鈥揕iAlH₄ could significantly enhance the absorption/desorption kinetics of MgH₂鈥揕iAlH₄. From the differential scanning calorimetry and Kissinger analysis, the apparent activation energy of the 5 mol % MnFe₂O₄-doped sample for the three decomposition stage is 55.8, 70.8, and 96.5 kJ/mol, resulting in a 45.7, 85.5, and 99.6 kJ/mol decrease, respectively, compared with the MgH₂鈥揕iAlH₄ sample. These improvements are mainly attributed to in situ formed Fe_0.872O phase and the amorphous Mn-containing phase during the dehydrogenation process, which act as the real catalyst in the MgH₂鈥揕iAlH₄ + 5 mol % MnFe₂O₄ composite.