Fluorinated Alumina Pillared α-Zirconium Phosphates as Supports for Metallic Nickel Catalysts

Two series of nickel catalysts supported on fluorinated alumina pillared α-zirconium phosphate materials have been prepared by the impregnation and ion-exchange methods, with metal loadings of 4, 10, 15, and 20 wt% for the former and 4 wt% for the latter. Temperature-programmed reduction profiles showed variable ranges of H2consumption, indicating that the reducibility of the Ni2+species is dependent on nickel loading and support characteristics, such as alumina content and surface area. X-ray photoelectron spectroscopy analysis and reduction studies with H2indicated that a fraction of the loaded Ni2+interacts with the support and cannot be reduced atT< 873 K. Samples were reduced at 773 and 873 K and their catalytic activity was probed in the reaction of hydrogenation of benzene. Despite the relatively low reduction and dispersion of metal found, the high-nickel-content catalysts displayed much higher activity than a reference Ni/Al2O3catalyst. Conversion to cyclohexane was maximum, i.e., 100%, for samples reduced at 773 K containing 15 and 20 wt% Ni. Deactivation of these catalysts was imperceptible for at least 20 h on-stream.