Title

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

Document Type

Article

Publication Date

2013

Digital Object Identifier (DOI)

https://doi.org/10.1021/jp410449q

Abstract

The catalytic effects of MnFe2O4 nanoparticles on the hydrogen storage properties of MgH2–LiAlH4, prepared by ball milling, are studied for the first time. The hydrogen storage properties and reaction mechanism are investigated by pressure–composition–temperature (PCT), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The nonisothermal desorption results show that MgH2–LiAlH4 + 5 mol % MnFe2O4 has a lower onset dehydrogenation temperature, 85, 50, and 40 °C lower than these of ball-milled MgH2–LiAlH4 sample for each stage in the dehydrogenation process. The isothermal dehydriding kinetics and isothermal rehydrogenation kinetics results indicate that adding MnFe2O4 to MgH2–LiAlH4 could significantly enhance the absorption/desorption kinetics of MgH2–LiAlH4. 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–LiAlH4 sample. These improvements are mainly attributed to in situ formed Fe0.872O phase and the amorphous Mn-containing phase during the dehydrogenation process, which act as the real catalyst in the MgH2–LiAlH4 + 5 mol % MnFe2O4 composite.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

The Journal of Physical Chemistry C, v. 117, issue 51, p. 26940-26947

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