Enhanced Hydrogen Storage Properties of LiAlH4 Catalyzed by CoFe2O4 Nanoparticles

Document Type

Article

Publication Date

2014

Digital Object Identifier (DOI)

https://doi.org/10.1039/C4RA00841C

Abstract

The catalytic effects of CoFe2O4 nanoparticles on the hydrogen storage properties of LiAlH4 prepared by ball milling were investigated. The onset desorption temperature of the LiAlH4 + 2 mol% CoFe2O4 sample is 65 °C, which is 90 °C lower that of the as-received LiAlH4, with approximately 7.2 wt% hydrogen released at 250 °C. The isothermal desorption results show that for the 2 mol% CoFe2O4 doped sample dehydrogenated at 120 °C, 6.8 wt% of hydrogen can be released within 160 min, which is 6.1 wt% higher than that of the as-received LiAlH4 under the same conditions. Through the differential scanning calorimetry (DSC) and the Kissinger desorption kinetics analyses, the apparent activation energy, Ea, of the 2 mol% CoFe2O4 doped sample is calculated as 52.4 kJ mol−1 H2 and 86.5 kJ mol−1 H2 for the first two decomposition processes. This is 42.4 kJ mol−1 H2 and 86.1 kJ mol−1 H2 lower compared with the pristine LiAlH4, respectively, indicating considerably improved dehydrogenation kinetics by doping the CoFe2O4 catalyst in the LiAlH4 matrix. From the Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses, a series of finely dispersed Fe and Co species with a range of valence states, produced from the reactions between LiAlH4 and CoFe2O4, play a synergistic role in remarkably improving LiAlH4 dehydrogenation properties. The rehydrogenation properties of the LiAlH4 + 2 mol% CoFe2O4 sample have also been investigated at 140 °C under 6.5 MPa pressure held for 2.5 h.

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Citation / Publisher Attribution

RSC Advances, v. 4, p. 18989-18997

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