Structural and surface propperties of Ni-Cu nanoparticles supported on SiO2

Nickel (1%) and nickel (1%)-copper (0.2–0.75%) metal phases supported on silica have been prepared by aqueous hydrazine reduction of nickel acetate at 70°C. They were characterized by XRD, TEM, H2-adsorption and TPD. The obtained results show that nickel is in a whisker-like shape or as a film of low density for the Ni/SiO2 and Ni-Cu/SiO2 systems respectively. The mean particle size is lower than 2 nm. Copper is in the shape of bigger facetted particles in the mono or bimetallic systems with a mean particle size of about 25 nm. The nickel phase dispersion, as determined by H2-adsorption, decreased in the presence of copper, as probably a result of Ni-Cu interactions. All the solids were found to be good hydrogen reservoir through the formation of H-spiltover species. The amounts of hydrogen stored changed with the copper content due to changes in the Ni-Cu interactions.