Superior Catalytic Effect of Nickel Ferrite Nanoparticles in Improving Hydrogen Storage Properties of MgH2

详细信息    查看全文

• 作者：Qi Wan ; Ping Li ; Jiawei Shan ; Fuqiang Zhai ; Ziliang Li ; Xuanhui Qu
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：February 12, 2015
• 年：2015
• 卷：119
• 期：6
• 页码：2925-2934
• 全文大小：579K
• ISSN：1932-7455

文摘

The catalysis of NiFe₂O₄ nanoparticles on the hydrogen storage performances of magnesium hydride synthesized by high-energy ball milling was studied for the first time. The H₂ storage performances and catalytic mechanism were studied by pressure鈥揷omposition鈥搕emperature (PCT), differential scanning calorimetry (DSC), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The nonisothermal dehydrogenation results display that the initial dehydrogenation temperature of 7 mol % NiFe₂O₄-doped MgH₂ is 191 掳C, which is 250 掳C lower than that of pristine MgH₂. The desorption kinetics displays that the MgH₂+7 mol % NiFe₂O₄ sample could desorb 3.79 wt % H₂ within 1 h at 300 掳C under H₂ pressure of 0.1 MPa. The absorption kinetics displays that the MgH₂+7 mol % NiFe₂O₄ sample could absorb 2.06 wt % H₂ within 3 h near room temperature under H₂ pressure of 4 MPa. The desorption activation energy of the MgH₂+7 mol % NiFe₂O₄ sample is 59.6 kJ/mol, decreasing 195.3 kJ/mol as compared with pristine magnesium hydride. The reaction enthalpy and entropy of the MgH₂+7 mol % NiFe₂O₄ sample during the dehydrogenation process are improved. The enhancement in the H₂ storage performances of MgH₂ by adding NiFe₂O₄ nanoparticles is primarily ascribed to intermetallic Fe₇Ni₃ and (Fe,Ni) phases during the desorption procedure, which act as the real catalyzer in the 7 mol % NiFe₂O₄-doped sample.