HYDRIDING PROPERTIES OF MG-BASED HYDROGEN STORAGE MATERIALS PREPARED CHEMICALLY FROM A HOMOGENEOUS PHASE

The dispersion of magnesium atoms into ammonia matrices at 77 K using a metal vapour technique gave rise to a homogeneous solution of dissolved magnesium metal in liquid ammonia. Use of the dissolution of magnesium metal in liquid ammonia enabled various types of novel Mg-based hydrogen storage materials to be prepared. In this study, hydrogen storage materials prepared using the solvent power of ammonia were of two types: (i) Active, small magnesium metals were crystallized out of the solution of magnesium dissolved in liquid ammonia; the crystallization was carried out in the presence or absence of catalytically active nickel powders (respectively, Mg-Ni or Mg). (ii) Magnesium metal was highly dispersed on an active carbon (AC) support with high surface area by impregnating the AC with the solution of magnesium dissolved in liquid ammonia (referred to as Mg/AC). By using AC on which active nickel, ruthenium or platinum metals had been highly dispersed, the preparation of samples was further extended to include binary systems (Mg-Ni/AC, Mg-Ru/AC or Mg-Pt/AC). The samples were characterized in connection with the preparation methods. These magnesium-based compounds were extremely active toward hydrogen absorption.