Preparation of high-activity MgO-supported Co-Mo and Ni-Mo sulfide hydrodesulfurization catalysts

CoO-MoO3/MgO and NiO-MoO3/MgO catalysts were prepared from MoO3/MgO by impregnation with methanol solutions of Co nitrate and Ni nitrate, respectively, followed by calcination at 350degreesC. The texture of the starting MoO3/MgO was preserved during this preparation. The hydrodesulfurization activity of the pre-sulfided catalysts was evaluated using the reaction of benzothiophene (1.6 MPa, 300-360degreesC). Commercial CoMo/Al2O3 (Shell 344) and NiMo/Al2O3 (Shell 324) catalysts were used as reference points of activity. A strong synergistic effects in activity between Co(Ni) and Mo in Co(Ni)Mo/MgO catalysts was observed with an optimum Co(Ni)O content of about 3-4 wt%. The most active Co(Ni)Mo/MgO catalysts were 1.5 to 2.3 times more active than their corresponding Al2O3-supported counterparts. MgO should be considered a new promising support for Co(Ni)Mo sulfide catalysts. However, its sensitivity to water and propensity, to form solid solutions with CoO and NiO must be taken into consideration in catalyst preparation. (C) 2002 Elsevier Science (USA).