Ni–Mo and Ni–W sulfide catalysts prepared by decomposition of binary thiometallates

Ni–Mo and Ni–W sulfide catalysts with atomic ratio R = 0.5 (Ni/(Ni + M), with M = Mo or W) prepared by decomposition of Ni-impregnated thiometallates were evaluated in the reaction of thiophene hydrodesulfurization. Catalysts derived from impregnated thiometallates (DTI samples) presented improved catalytic activity and higher synergistic effect than catalysts prepared by co-precipitation (HSP samples) despite the fact that co-precipitated catalysts showed larger surface area. Structure characterization by high-resolution electron microscopy (HREM) and X-ray diffraction (XRD) revealed different crystalline phases in DTI and HSP catalysts. A mixture of phases (MS2, NiS1.03 and MO2) was observed in catalysts obtained by co-precipitation. Only the poorly crystalline MS2 phase was observed in DTI catalysts suggesting that the Ni promoter is very well dispersed on the chalcogenide structure.