Low-temperature hydrogen desorption and the structural properties of spark discharge generated Mg nanoparticles

Mg nanoparticles were synthesized using spark discharge, resulting in large-scale structures of agglomerated nanoparticles with primary particle sizes of similar to 10 nm, surrounded by MgO shells 1-2 nm thick. Thermal hydrogen desorption starts at remarkably low temperatures of similar to 350 K, related to the small sizes of particles, and extends over a broad temperature range to beyond 700 K, caused by the presence of oxide shells acting as activation barriers. The hydrogen sorption kinetics is increased significantly by adding Pd nanoparticles in situ during synthesis, showing the versatility of spark discharge generation for the production of metal hydride nanocomposites. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.