TiO2- and SiO2-supported, 10% by mass cobalt Fischer-Tropsch (F-T) catalyst
s, loaded with low concentrations of sulfur (100-2000 ppm) from different s
ources ((NH4)(2)S, (NH4)(2)SO4, and (NH4)(2)SO3), have been synthesized and
characterized using DRIFTS and TPR. CO adsorption and FT reaction, monitor
ed by DRIFTS, revealed that small amounts of sulfur (100 ppm) increased the
strength of most types of metal-CO interactions and enhanced F-T catalyst
activity, as reflected by more intense metal-CHx infrared intensities relat
ive to the unsulfided catalyst. Sulfur concentrations between 200 and 2000
ppm gave infrared spectra with decreased intensity of the absorbance peaks
due to adsorbed hydrocarbons. It was found that the presence of sulfur resu
lted in a slight increase in the reduction temperature of the titania-suppo
rted catalysts. Sulfur on the surface of the silica supported catalysts dec
reased the intensity of the TPR peak related to a reducible silicate. (C) 1
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