| dc.description.abstract | The effect of nickel promotion in cobalt Fischer-Tropsch catalysts towards reducibility
and cobalt dispersion was investigated. A series of catalysts loaded
with 20% Co and 0-10% Ni on gamma-alumina were impregnated by the incipient
wetness method and calcinated in two steps: First with Ni, then Co.
Reducibility was studied with TPR and compared with data from in-situ XRD
and TGA. Particle sizes and dispersion was studied with chemisorption, in-situ
and ex-situ XRD. Sintering of cobalt particles during reduction and at elevated
temperatures was also studied with in-situ XRD.
Promotion with Ni was shown to decrease the reduction temperature of the
first reduction step of cobalt oxide, while not influencing the second reduction
step towards metallic Co. Ni promotion was also shown to increase dispersion
by inhibiting sintering of Co particles both during the second reduction step
towards metallic Co, and at elevated temperatures. | |
