Abstract: A highly active sulfided NiPMo/MCM-41 (NiPMo-S/M41) hydrodesulfurization (HDS) catalyst was successfully synthesized using Keggin-type phosphomolybdic acid as the phosphorus and molybdenum source, and thioacetamide as the sulfur source. The supported NiPMo/M41, Ni2P-Mo/M41 and Ni2P/M41 catalysts were also prepared to investigate the effects of Mo, S, and Keggin structure on the HDS performance of the catalysts. The HDS activities of NiPMo/M41 and NiPMo/M41-S for dibenzothiophene (DBT) were much higher than that of Ni2P-Mo/M41, demonstrating that the active phases in the Keggin-structured catalysts were significantly superior than that of the Mo-modified Ni2P phase. The HDS activity of the catalysts followed the order NiPMo/M41-S (96.7%) > NiPMo/M41 (89.9%) > Ni2P-Mo/M41 (53.5%) > Ni2P/M41 (48.9%). For all the Ni2P/M41, Ni2P-Mo/M41 and NiPMo/M41 catalysts, phenyl cyclohexane (CHB) was formed in small concentrations (<21.0%), indicating that direct desulfurization (DDS) was the favored reaction route and that it did not change for Keggin-structured NiPMo/M41. What’s more, the selectivity towards CHB of NiPMo/M41-S increased to 44.6%, much higher than that of NiPMo/M41 catalyst (17.6%), showing the sulfurization deduced the improved hydrogenation ability, which was attributed to the metal-acid synergistic effect.

Key words: Keggin-type phosphomolybdic acid, Hydrodesulfurization, Dibenzothiophene