Journal of Catalysis, Vol.169, No.1, 317-326, 1997
Fluorinated Alumina Pillared Alpha-Zirconium Phosphates as Supports for Metallic Nickel-Catalysts
Two series of nickel catalysts supported on fluorinated alumina pillared alpha-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 H-2 consumption, 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 Ha indicated that a fraction of the loaded Ni2+ interacts with the support and cannot be reduced at T < 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/Al2O3 catalyst. 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.
Keywords:X-RAY PHOTOELECTRON;ZEOLITE CATALYSTS;HYDROGENATION;REDUCTION;CHEMISORPTION;DISPERSION;DIFFRACTION;TEMPERATURE;BENZENE;LITHIUM