Modification of γ-alumina by barium and lanthanum, and the consequential effect on the reducibility and dispersibility of nickel

Abstract

The influence of modifiers such as barium and lanthanum on the physical properties of γ-alumina has been studied. Calcination of the modified alumina at 723 K for 5 h does not result in any compound formation as evidenced from X.r.d. Ca. 8–9 wt% nickel was prepared by impregnation method using this modified alumina. Ba and La modifiers improve the reducibility of nickel and the metal area measured by hydrogen adsorption. It is presumed that the oxide layers over the surface of alumina prevent the interaction between nickel and γ-Al₂O₃, making more nickel available on the surface. The activity and turnover number (TON) for benzene hydrogenation vary directly with the available metal area, irrespective of the modifier.