Synthesis and Catalytic Properties for Phenylacetylene Hydrogenation of Silicide Modified Nickel Catalysts
Interstitial silicide modified nickel, with high selectivity in some hydrogenation reactions, had been produced by dissolving silicon atoms into the nickel lattices. The metallic nickel was obtained by reducing the as prepared high surface area NiO, followed by modification of the bulk nickel through silification of silane/H2 at relatively low temperature and atmospheric pressure. The as prepared materials were characterized by X ray diffraction, magnetic measurements, X ray photoelectron spectroscopy, transmission electron microscopy, energy dispersive X ray spectroscopy, and temperature programmed reduction. The results show nickel silicide formation involves the following sequence as a function of increasing temperature: Ni (cubic) Ni2Si (orthorhombic) NiSi (orthorhombic) NiSi2 (cubic) The insertion of Si atoms into the interstitial sites between Ni atoms resulted in a significant change in the unit cell lattice of nickel. All of the silicide modified nickel materials were ferromagnetic at room