FLUORINATED ALUMINA PILLARED ALPHA-ZIRCONIUM PHOSPHATES AS SUPPORTS FOR METALLIC NICKEL-CATALYSTS

Two series of nickel catalysts supported on fluorinated alumina pillar ed alpha-zirconium phosphate materials have been prepared by the impre gnation and ion-exchange methods, with metal loadings of 4, 10, 15, an d 20 wt% for the former and 4 wt% for the latter. Temperature-programm ed reduction profiles showed variable ranges of H-2 consumption, indic ating that the reducibility of the Ni2+ species is dependent on nickel loading and support characteristics, such as alumina content and surf ace area. X-ray photoelectron spectroscopy analysis and reduction stud ies with Ha indicated that a fraction of the loaded Ni2+ interacts wit h 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 react ion of hydrogenation of benzene. Despite the relatively low reduction and dispersion of metal found, the high-nickel-content catalysts displ ayed much higher activity than a reference Ni/Al2O3 catalyst. Conversi on to cyclohexane was maximum, i.e., 100%, for samples reduced at 773 K containing 15 and 20 wt% Ni. Deactivation of these catalysts was imp erceptible for at least 20 h on-stream. (C) 1997 Academic Press.