MgH 2 –ZrFe 2 H x nanocomposites for improved hydrogen storage characteristics of MgH 2

Microstructure and hydrogen storage kinetics of Mg89RE11 (RE = Pr, Nd, Sm) binary alloys

“…The nal hydrogen desorption capacity of 5.0 wt% for the alloy is lower than the hydrogen absorption capacity. Length of time for the completion of hydrogen desorption of the hydrogenated alloy at 320 C, 340 11 (RE ¼ Pr, Nd, Sm) alloys, the order of hydrogen absorption and desorption rate is Sm > Nd > Pr. However, the apparent activation energy (E a ) both absorption and desorption course are all decreased, and the order is Sm < Nd < Pr.…”

“…So far, a variety of chemical elements, such as In, [5][6][7] Ni, [8][9][10] Zr, 11,12 Ag, 13 Al, 14,15 Ti, 16,17 rare earth (RE) elements 18 and their composites, [19][20][21][22][23] have been exploited as the alloying elements for the Mg-based alloys. Among them, adding RE elements attracts extensive interest for the Mg-based alloys due to its excellent improvement of the hydriding/dehydriding rate, which may be a better choice to meet the requirements of future hydrogen energy storage systems.…”

Catalytic Application of Carbon‐based Nanostructured Materials on Hydrogen Sorption Behavior of Light Metal Hydrides

“…It is now well known that the rate of dehydrogenation reaction depends upon the decomposition of Mg(NH 2 ) 2 and the transition metal particles enhance the de-/rehydrogenation characteristics of the Mg(NH 2 ) 2 /LiH mixture [27]. The used CNSs also have Fe and Ni nanoparticles have a benefi cial effect on the sorption behavior of Li-Mg-N-H.…”

“…The used CNSs also have Fe and Ni nanoparticles have a benefi cial effect on the sorption behavior of Li-Mg-N-H. The possible approach towards mechanism may be dealt with in the presence of unpaired subshell in synthesisacquired Fe (3d 6 ) and Ni (3d 8 ) nanoparticles which have a tendency to interact with the lone pair of electrons of nitrogen atom, hence weakening the Mg-N bond in the Mg(NH 2 ) 2 /LiH mixture [27]. It may also be pointed out that even without the synthesis-acquired metal particles the catalytic effect of these nanostructures arises due to the curvature effect (electron affi nity) of carbon nanostructures [41,107].…”

Improvement in the hydrogen storage performance of the as-milled Sm–Mg alloys using MoS2 nano-particle catalysts

“…Lin et al 25 reported a symbiotic CeH 2.73 /CeO 2 catalyst to enhance the hydrogen storage capacity of MgH 2 and demonstrated that a spontaneous hydrogen release effect in the interface region of the symbiotic CeO 2 /CeH 2.73 nano-particle played a role as an efficient "hydrogen pump". Shahi et al 26 milled an intermetallic hydride, ZrFe 2 H x , with MgH 2 to synthesize the MgH 2 -ZrFe 2 H x nanocomposites and found that ZrFe 2 H x led to a decrease in the dehydrogenation temperature from 410 C to 290 C. Furthermore, it signicantly improved the hydrogenation kinetics, as observed by the lowered activation energy of $61 kJ mol À1 H 2 . El-Eskandarany et al 27 used the reactive ball milling (RBM) method to prepare MgH 2 /5Ni/5Nb 2 O 5 nanocomposite powders, which exhibited an excellent hydriding/dehydriding performance, as evidenced by the short time required to absorb (41 s) and desorb (121 s) 5 wt% H 2 at 250 C. Although numerous new achievements have been reported, further efforts are urgently necessary to enhance the hydrogen storage performance of the Mg-based alloys.…”