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), wi th 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 c atalytic activity and higher synergistic effect than catalysts prepared by co-precipitation (HSP samples) despite the fact that co-precipitated cataly sts showed larger surface area. Structure characterization by high-resoluti on electron microscopy (HREM) and X-ray diffraction (XRD) revealed differen t crystalline phases in DTI and HSP catalysts. A mixture of phases (MS2, Ni S1.03 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.