Enhanced hydrogen storage properties of LiAlH 4 catalyzed by CoFe 2 O 4 nanoparticles

• Published in: RSC advances 2014, Vol.4 (36), p.18989-18997
• Main Authors: Li, Ziliang, Zhai, Fuqiang, Wan, Qi, Liu, Zhaojiang, Shan, Jiawei, Li, Ping, Volinsky, Alex A., Qu, Xuanhui
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C4RA00841C

The catalytic effects of CoFe 2 O 4 nanoparticles on the hydrogen storage properties of LiAlH 4 prepared by ball milling were investigated. The onset desorption temperature of the LiAlH 4 + 2 mol% CoFe 2 O 4 sample is 65 °C, which is 90 °C lower that of the as-received LiAlH 4 , with approximately 7.2 wt% hydrogen released at 250 °C. The isothermal desorption results show that for the 2 mol% CoFe 2 O 4 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 LiAlH 4 under the same conditions. Through the differential scanning calorimetry (DSC) and the Kissinger desorption kinetics analyses, the apparent activation energy, E a , of the 2 mol% CoFe 2 O 4 doped sample is calculated as 52.4 kJ mol −1 H 2 and 86.5 kJ mol −1 H 2 for the first two decomposition processes. This is 42.4 kJ mol −1 H 2 and 86.1 kJ mol −1 H 2 lower compared with the pristine LiAlH 4 , respectively, indicating considerably improved dehydrogenation kinetics by doping the CoFe 2 O 4 catalyst in the LiAlH 4 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 LiAlH 4 and CoFe 2 O 4 , play a synergistic role in remarkably improving LiAlH 4 dehydrogenation properties. The rehydrogenation properties of the LiAlH 4 + 2 mol% CoFe 2 O 4 sample have also been investigated at 140 °C under 6.5 MPa pressure held for 2.5 h.