Metal Organo-Clays as potential adsorbents for hydrogen storage

A. Azzouz, S. Nousir, N. Bouazizi, R. Roy
University of Quebec at Montreal, CA

Keywords: clay minerals, metal nanoparticle, dendrimers, hydrogen storage

Summary:

Metal-Organo-Clays (MOC) are novel microporous matrices that can be synthesized via the in-situ formation of Cu, Fe or Pd nanoparticles in montmorillonite-supported polyol dendrimers. This is a new concept that has scarcely been tackled so far. For this purpose, various dendrimers such as Boltorn H20, thioalcohols and aminoalcohols were incorporated via physical clay mineral intercalation or by chemical grafting of 3-amino-propyl-triethoxysilane (3-APTES) as precursor. Thermal-programmed-desorption of carbon dioxide (CO2-TPD) showed a direct linear proportionality between the amount of retained CO2 and the number of incorporated OH groups. The latter were found to contribute to the stabilization of the metal nanoparticles in the dendrimer entanglement. Hydrogen-TPD analysis revealed that the incorporation of Me-NNPs promotes interaction with molecular hydrogen. Me-NNPs were found to act as the main adsorption sites for hydrogen. At normal pressure, hydrogen adsorption appears to involve only weak interaction with NNPs, inasmuch as hydrogen desorption was possible at almost ambient temperature. When thioalcohol based dendrimers were used, insights through transmission electron microscopy revealed that the presence of sulfur atoms favors a more homogenous dispersion of Me-NNPs, as compared to aminoalcohol dendrimers. The results presented herein open new prospects for truly reversible hydrogen storage.