How modifiers can influence the properties of Ni/gamma-Al2O3 catalysts

The object of the present studies was the characterization of modified Ni/gamma-Al2O3 catalysts. During the course of these investigations, two main classes of modifiers were utilized having an effect on: (i) the active catalyst phase; and (ii) the support and the active-phase/support interaction. Support modification was conducted by utilizing gaseous ammonia (for the modification of gamma-alumina) and/or organic reagents (mainly EDTA - ethylenediaminetetraacetic acid - and its disodium salt) in the nickel catalyst preparation. These procedures allowed the generation of relatively small Ni crystallites in the final catalysts (after temperature treatment and activation). The various steps in the preparation were characterized by spectroscopic methods (mainly infrared). The controlled surface reaction (CSR) between tetraethyltin and hydrogen adsorbed on nickel was utilized for modification of the active phase of the catalysts. Hydrogenolysis of simple alkanes (e.g. ethane, propane and n-butane) in a gradientless reactor was utilized as a catalytic test reaction for the catalysts prepared.