Synthesis of nanocrystalline MgH2 powder by gas-phase condensation and in situ hydridation:: TEM, XPS and XRD study

In this work, a two-step method for the preparation of nanocrystalline MgH2 is presented, where the first step consists of synthesis of nanocrystalline Mg powder by the gas-phase condensation method (GPC and the second of in situ hydridation leading to the formation of MgH2 nanoparticles. By transmission electron microscopy (TEM) and electron diffraction (ED), crystalline Mg nanoparticles from GPC were found to have mean size within the range of 30-50 nm, while in the case of MgH2, nanoparticles these values increase approximately 2-3 times mainly due to particles growth during the hydridation step. The X-ray diffraction (XRD) analysis shows the high conversion into the MgH2 phase after hydridation. By X-ray photoelectron spectroscopy (XPS) metallic magnesium was detected below a magnesium oxide layer of 3-4 nm for the Mg sample prepared by GPC, which shows the efficiency of a novel sample transfer system without air exposure between N-2-glove-box, preparation chamber and experimental apparatus.(C) 2006 Elsevier B.V. All rights reserved.