α-Alumina-Supported Nickel Catalysts Prepared with Nickel Acetylacetonate. 1. Adsorption in the Liquid Phase

Nickel acetylacetonate was used as a precursor for the preparation of Ni/Al 2 O 3 catalysts with metal content between 0.4 and 3 wt %. The nature of the interactions between the metal complex and the support has been investigated by X-ray photoelectron (XPS) and infrared (IR) spectroscopies. The spectral features point to modifications of the precursor in the adsorbed state. IR results indicate that the interaction between acetylacetone and the support involves coordinately unsaturated (cus) Al 3+ sites, hydroxyls of the support surface, and probably also basic oxygens. A model for these interactions is proposed. Monolayer coverage is achieved at a Ni loading of about 0.8−1.0%. Piling in multilayers occurs at higher content.