Competitive HDS and HDN reactions over NiMoS/HMS-Al catalysts: Diminishing of the inhibition of HDS reaction by support modification with P

• Sulfided catalysts were tested in simultaneous HDS of DBT and HDN of carbazole.
• The most active catalyst was prepared with 1.0 wt% of P.
• All catalysts followed the same volcano-type trend for both HDS and HDN activities.
• The HDS activity was greatly suppressed upon increasing carbazole concentration.

Individual and simultaneous hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrodenitrogenation (HDN) of carbozole reactions have been studied in the presence of hydrogen (P = 55 bar) at 310 °C in a batch reactor over a series of sulfided NiMo/P/Al-HMS catalysts modified with phosphorus (0.5–2.0 wt%). Both oxidic precursors and sulfide catalysts have been characterized by specific surface area, XRD, Raman, TPD-NH3, HRTEM, XPS and IR spectroscopy of adsorbed pyridine. Regardless of the reaction studied, all P-containing catalysts showed higher activity than that to the P-free one. The catalyst modified with optimized amount of P (1 wt%) the best HDS activity and exhibited a lowest inhibition factor during simultaneous HDS and HDN, which was close to that of a commercial NiMo/Al2O3 sulfide catalyst. This was linked with formation of irregular MoS2 structures having high concentration of brim sites as well as with its largest total acidity.

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