Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS2/Al2O3 Catalyst and Its Application in Hydrodesulfurization

A novel impregnation–deposition method was applied to prepare presulfided MoS2/Al2O3 catalysts with large surface areas for the application of hydrodesulfurization (HDS). The synthesized catalysts were characterized systematically, and their catalytic performances were evaluated by the HDS of dibenzothiophene (DBT). It is found that the impregnation–deposition method improves the surface area of the synthesized catalysts by eliminating the micropores of the alumina support and adding mesostructured MoS2 particles within the support. Moreover, this method enhances the reducibility of the sulfided Mo species, as characterized by temperature-programed reduction (TPR) and X-ray photoelectron spectroscopy. Compared to the impregnation method, the impregnation–deposition method leads to the formation of more active sites as proved by TPR and CO-Fourier-transform infrared analyses. Hence, the reaction conversion rates and the hydrogenation/direct-desulfurization ratios of the DBT on the catalysts synthesized by the impregnation–deposition method are 1.3 times and 1.5 times as high as those of the catalysts made by the conventional impregnation method, respectively.