Characterizations and HDS performances of sulfided NiMoW catalysts supported on mesoporous titania-modified SBA-15

Abstract

This work studies the effect of the support modifications (SBA-15) with Ti by using a ternary system as an active phase (Ni, Mo, W). Calcined and sulfided catalysts were characterized by a variety of techniques such as XRD, SBET, TPR, TPD-NH3, DRS-UV–vis, micro-Raman spectroscopy and HRTEM. Sulfided catalysts were tested in the hydrodesulphurization (HDS) of dibenzothiophene (DBT) performed in a batch reactor at 320°C and total hydrogen pressure of 800psi. This reaction was selected for the catalyst screening because DBT is a typical sulfur-containing hydrocarbon present in high-boiling petroleum fractions and coal derived liquids and the absence of any diffusion limitation for DBT molecule to entry into the porous structure of the SBA-15 supported catalysts. We observed that the incorporation of Ti did not decrease the catalytic activity in the HDS of DBT reaction except for Si/Ti=40 catalyst. UV–vis analyses show a higher amount of tetrahedral species for CAT/40TiS15 in counterpart with CAT/60TiS15 that showed a lower amount of those species however, the lower amount of Ti in the catalyst (CAT/60TiS15) showed the highest hydrogenation capability among the catalysts studied (HYD/DDS=0.81) despite the main route in the HDS of DBT reaction was the direct desulfurization (DDS) pathway (selectivity).