PREPARATION OF NI AL2O3 CATALYSTS FROM VAPOR-PHASE BY ATOMIC LAYER EPITAXY/

Ni/Al2O3 catalysts were prepared by saturating gas-solid reactions as an atomic layer epitaxy (ALE) process. Vaporized Ni(acac)2 was chemiso rbed on a porous alumina support, and the produced surface complex was then air treated to remove the ligand residues. The nickel content co uld be precisely controlled by repeating this reactor cycle. On alumin a preheated at 800-degrees-C, the nickel content varied from 3 to 21 w t%, when the number of reaction cycles was increased from one to ten. The performance of the Ni-catalysts was evaluated in the gas-phase hyd rogenation of toluene. The preheat temperature of alumina influenced t he activity of the catalyst, and a maximum in the activity was observe d for catalysts prepared from alumina preheated at 875-degrees-C. Cata lysts prepared by four reaction cycles, containing about 10 wt% nickel , gave the highest utilization of nickel.