Abstract: A new type of MoNiP/Al2O3 catalyst for thiophene hydrodesulfurization was prepared by the co-impregnation method, wherein a suitable amount of citric acid was added in the Mo-Ni-P-O impregnation solution. The catalyst exhibits high activity for thiophene hydrodesulfurization under presulfidation- and calcination-free conditions. The catalyst was characterized by N2 adsorption, temperature-programmed reduction,X-rayphotoelectron spectroscopy, infrared spectroscopy, and elemental analysis methods. The effects of citric acid on the structure and activity of the MoNiP/Al2O3 catalyst were studied. The results show that the addition of citric acid weakens the interaction between the active metal components and support, improves dispersion of active metal components on the support surface, and promotes the reduction and sulfidation of the catalyst by sulfur-containing feedstocks. Therefore, the hydrodesulfurization activity of the catalyst is improved.

Key words: molybdenum, nickel, phosphorus, alumina, presulfidation-free, thiophene, hydrodesulfurization