Abstract The HDS activity of a commercial NiMo catalyst has been followed versus the amount of vanadium added to it, either by an oxidic procedure before the sulfidation step or by a sulfided route, using a highly soluble vanadyl porphyrin simulating the industrial process on the presulfided catalyst. An oxidative regeneration followed by a resulfidation transformed these porphyrinpoisoned catalysts into the oxidic preparation family. At the ...
