Effect of surface modification of the support of hydrotreating catalysts with transition metal oxides (sulfides) on their catalytic properties

CoMo/MeO _x (S _y )/Al₂O₃ catalysts have been synthesized on supports modified with oxides (sulfides) of transition metals (Co, Ni, Mn, and Zn) using decamolybdodicobaltic heteropoly acid H₆Co₂Mo₁₀O₃₈H₄]. A correlation between the activity of the catalysts and the ability of transition metal sulfides to accumulate molecular hydrogen has been found in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and in the hydrotreating of the diesel fraction. It has been shown that the presence on the surface of Al₂O₃ of sulfides (NiS _x , CoS _x ) capable of activating hydrogen has a positive effect on the activity of the supported catalysts. It has been found that the hydrogen spillover effect, which was studied in a range of 300–350°C, contributes to an increase in the hydrogenating function of the catalyst systems.