Hydrodesulfurization activity of NiMo/TiO2-Al2O3 catalysts

The hydrodesulfurization activities and other physico-chemical properties of TiMo/TiO2-Al2O3 catalysts were studied and compared with those of a commercial NiMo/Al2O3 catalyst. The TiO2-Al2O3 mixed oxides carrier was prepared by impregnating Al2O3 With an ethanol solution of TiCl4 or an isopropanol solution of Ti(C4H9O)(4). The active component MoO3 and the promoter NiO were supported by impregnation of a mixed solution of Ni(NO3)(2) . 6H(2)O and (NH4)(6)Mo7O24. 4H(2)O. BET measurements showed no large decrease of surface area or pore volume for the carrier and catalyst-containing TiO2. LRS data demonstrated that TiO2 on Al2O3 was present as the anatase phase, and only the vibration band of Mo=O at 960 cm(-1) appeared over NiMo/TiO2-Al2O3 when TiO2 loading was less than 20 wt %. TPS results reveal that the presence of TiO2 can facilitate sulfidation of Mo-O species. Catalytic activity measurements showed that NiMo/TiO2-Al2O3 catalysts without presulfiding exhibited very high HDS activity for a model reactant containing 100 ppm thiophene or industrial naphtha. The capability of sulphur removal over the non-pretreated NiMo/TiO2-Al2O3 catalyst is even better than over a sulfided commercial hydrotreating NiMo/Al2O3 catalyst. (C) 1998 Elsevier Science B.V