Enhancement of the selective hydrodesulfurization performance by adding cerium to CoMo/gamma-Al2O3 catalysts

A series of cerium-modified CoMo/Al2O3 hydrodesulfurization (HDS) catalysts were prepared to enhance catalytic activity and improve selectivity during the selective HDS of fluid catalytic cracking gasoline. The morphology properties of the catalysts with different amounts of CeO2 were characterized by physical techniques and correlated with their catalytic performance. Results clearly indicated that Ce introduction weakened the interaction between support and metal and promoted sulfidation of the Mo species with the formation of more CoMoS active phases. This phenomenon induced a positive effect on the morphology of MoS2 particles, which significantly influenced the catalytic performance. A linear correlation existed between hydrodesulfurization selectivity and Mo dispersion. By optimizing the amount of CeO2 loading, the catalyst with 1.0 wt% CeO2 incorporation exhibited the best HDS selectivity with the highest sulfidation, the largest number of CoMoS active phases and the lowest Mo dispersion.