Metallic glassy Zr70Ni20Pd10 powders for improving the hydrogenation/dehydrogenation behavior of MgH2

Abstract

Because of its low density, storage of hydrogen in the gaseous and liquids states possess technical and economic challenges. One practical solution for utilizing hydrogen in vehicles with proton-exchange fuel cells membranes is storing hydrogen in metal hydrides. Magnesium hydride (MgH2) remains the best hydrogen storage material due to its high hydrogen capacity and low cost of production. Due to its high activation energy and poor hydrogen sorption/desorption kinetics at moderate temperatures, the pure form of MgH2 is usually mechanically treated by high-energy ball mills and catalyzed with different types of catalysts. These steps are necessary for destabilizing MgH2 to enhance its kinetics behaviors. In the present work, we used a small mole fractions (5 wt.%) of metallic glassy of Zr70Ni20Pd10 powders as a new enhancement agent to improve its hydrogenation/dehydrogenation behaviors of MgH2. This short-range ordered material led to lower the decomposition temperature of MgH2 and its activation energy by about 121 °C and 51 kJ/mol, respectively. Complete hydrogenation/dehydrogenation processes were successfully achieved to charge/discharge about 6 wt.%H2 at 100 °C/200 °C within 1.18 min/3.8 min, respectively. In addition, this new nanocomposite system shows high performance of achieving continuous 100 hydrogen charging/discharging cycles without degradation.

Recent developments in the fabrication, characterization and implementation of MgH2-based solid-hydrogen materials in the Kuwait Institute for Scientific Research

“…Obviously, using such pressurized hydrogen gas tanks as a source of fuel in vehicles is not safe and intensive research must be dedicated to improving the structural and mechanical properties of the materials used in the manufacture of the tanks. 24 Moreover, compressed hydrogen gas systems have low volumetric hydrogen storage densities. 25 Cryo-compressed hydrogen storage (CcH 2 ) and liquid hydrogen (LH 2 ) storage are alternative mature approaches in which hydrogen is liquidized at À253 C and compressed into vessels that can be pressurized to 250-350 atm.…”

“…Metallic Mg and Mg-based materials have been considering as the most important candidate hydrogen storage materials for use in real applications. [19][20][21][22][23][24]36 The worldwide interest in Mg is attributed to its natural abundance, low cost, light weight, and its high gravimetric (7.60 wt%) and volumetric (110 g l À1 ) hydrogen storage capacities. Recently, it has been reported that waste Mg-based alloys such as Mg-Al 39 and Mg-Gd 40 were successfully used as feedstock materials to produce a good quality of MgH 2 .…”

“…The rst report of using metallic glassy (MG) Zr 70 Ni 20 Pd 10 nanopowders as a catalytic agent to enhance the hydrogenation/ dehydrogenation kinetics of MgH 2 was introduced by El-Eskandarany in 2016. 24 In his work, nanocrystalline MgH 2 powders prepared using the RBM technique were doped with small mole fractions (5 wt%) of MG-Zr 70 Ni 20 Pd 10 powders and then high energy ball-milled for 50 h under 50 bar of H 2 . The HRTEM image taken near the edge of the MgH 2 /5 wt% amorphous Zr 70 Ni 30 Pd 10 composite particle obtained aer 50 h of RBM time is shown in Fig.…”

In-situ catalyzation approach for enhancing the hydrogenation/dehydrogenation kinetics of MgH2 powders with Ni particles

“…It is therefore natural to expect not only the development of new Ni-based catalysts (e.g. Ni-Zr15, ZrPdNi5) but also the replacement of known noble-metal-based catalysts by reliable Ni and Ni-based analogs.…”

“…Hydrogen is an energy carrier, which holds tremendous promise as a new clean energy option23. It is a convenient, safe, versatile fuel source that can be easily converted to a desired form of energy without releasing harmful emissions45. A key advantage of hydrogen is that when burned, carbon dioxide (CO 2 ) is not produced.…”