NaAlH₄ dehydrogenation properties enhanced by MnFe₂O₄ nanoparticles

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• 作者：Qi Wan ; Ping Li ; Ziliang Li ; Kuifei Zhao ; Zhiwei Liu ; Ling Wang ; Fuqiang Zhai ; Xuanhui Qu ; Alex A. Volinsky
• 关键词：Manganese ferrite ; Hydrogen storage ; Sodium alanate ; Dehydriding temperature ; Apparent activation energy
• 刊名：Journal of Power Sources
• 出版年：15 February, 2014
• 年：2014
• 卷：248
• 期：Complete
• 页码：388-395
• 全文大小：1157 K

文摘

The catalytic effects of MnFe₂O₄ nanoparticles on the dehydrogenation properties of NaAlH₄, prepared by ball milling, are investigated. The onset temperatures for NaAlH₄聽+聽7聽mol% MnFe₂O₄ are 95聽掳C, 152聽掳C and 327聽掳C for the three dehydrogenation steps, significantly lower compared with as-received NaAlH₄. The isothermal dehydriding kinetics shows聽that adding MnFe₂O₄ to NaAlH₄ could significantly enhance the desorption kinetics of NaAlH₄, 7聽mol% MnFe₂O₄-doped sample also displays the well-maintained kinetics and only a slight capacity loss for the three cycles. From the differential scanning calorimetry and the Kissinger desorption kinetics analysis, the apparent activation energy of the 7聽mol% MnFe₂O₄-doped sample for the three steps is 57.74聽kJ聽mol^鈭?, 75.06聽kJ聽mol^鈭? and 117.22聽kJ聽mol^鈭?, resulting in 56.05聽kJ mol^鈭?, 67.53聽kJ聽mol^鈭? and 59.12聽kJ聽mol^鈭? reduction, respectively, compared with the as-received NaAlH₄. Based on the Fourier Transform Infrared Spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, Fe_0.9536O and amorphous Mn or Mn-containing species together play a synergistic role in remarkably improving NaAlH₄ dehydriding properties.