Improvement of hydrogen storage characteristics of catalyst free magnesium nanoparticles prepared by wet milling

Abstract

Magnesium is one of the potential candidates for on-board hydrogen storage, but slow hydrogenation kinetics and unfavourable thermodynamics limits its practical implementation. To improve the hydrogenation characteristics, nanocrystalline magnesium was prepared by a simple wet milling method without addition of heavy metal catalyst. Compared to micro-crystalline Mg, developed nanocrystalline Mg exhibits improved hydrogen storage properties showing extended plateau region in the pressure-composition-temperature curves with higher hydrogen storage capacity (6.24 wt% at 300 C). Hydrogenation and dehydrogenation kinetics is found to follow KolmogorovÀJohnsonÀ MehlÀAvrami activation energy model confirming the involvement of nucleation-growth-impingement mechanism. Prolonged ball milling leads to quite fast hydrogenation kinetics (upto 90% of the saturation value in 15.5 minutes at 250 C) and leads to substantial decrease in the activation barrier. The activation energy for hydrogenation is found to be 68.88 kJ mol À1 for 8 hours ball milled sample. Present study established a simple and scalable method for nanocrystalline Mg, which can undergo reversible hydrogen absorption and desorption with improved performance without using any additional catalyst.

Plasmonic Hydrogen Sensors

“…Nevertheless, if Mg is properly prepared and incorporated with catalysts, these drawbacks can be overcome. He et al showed that for 2.25% V decorated Mg nanoblade array, [ 118,119 ] the hydrogen absorption activation energy can be reduced to 35 kJ mol −1 H 2 (compared to 65–81 kJ mol −1 H 2 for Mg powder) [ 120 ] and desorption activation energy to 65 kJ mol −1 H 2 (compared to 120–156 kJ mol −1 H 2 for MgH 2 powder). [ 121 ] In addition, the current review shows that Pd binary or ternary alloys can also be used to significantly improve the performance of PHS, but systematic studies on the fabrication and optical properties of these or other alloys are rare.…”

Positron Annihilation Spectroscopy Complex for Structural Defect Analysis in Metal–Hydrogen Systems

“…Milled MPF-4 magnesium powder of high purity (99.2%) with a particle size of 50–300 µm was used as the investigated material [ 22 , 23 , 24 , 25 ]. Magnesium hydride powder and dehydrogenated MgH 2 powder were also used for testing.…”

Nanointerface Engineering of Metal Hydrides for Advanced Hydrogen Storage

“…In this respect, diverse strategies for tackling such hostile thermodynamic and kinetic properties of unmodified hydride materials have been explored, including nanosizing hydrides and incorporating additive species. In particular, it has been widely shown that the nanosizing of hydride materials can induce distinct changes in thermodynamic ,− and kinetic properties, − improving the hydrogen storage performance compared to those of the bulk counterparts for both metal hydrides and complex hydrides …”