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

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 degrees 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. (C) 2015 Elsevier B.V. All rights reserved.