Sulfided Ni-Mo catalysts prepared by homogeneous sulfide precipitation
(HSP) and impregnated thiosalt decomposition (ITD) methods were used
in thiophene HDS, pyridine HDN, and simultaneous HDS/HDN reactions. Al
l catalysts were characterized by BET surface area measurement, X-ray
diffraction, laser Raman spectroscopy, and X-ray photoelectron spectro
scopy. The effect of various reaction parameters such as catalyst comp
osition, method of catalyst synthesis, reaction temperature, and react
ion pressure on catalytic behavior has been investigated. The inhibiti
on/enhancement effects in simultaneous HDS/HDN reactions were also exa
mined. The studies conducted over the unsupported catalysts present tr
ends very similar to those obtained over the supported catalysts and s
uggest the intrinsic nature of active sites to be essentially independ
ent of the support.