Synthesis, application and kinetic modeling of CeOx–Si–CoMo catalysts for the hydrodesulfurization of dibenzothiophene†
The ultradeep hydrodesulfurization (HDS) of fuel with a highly robust catalyst is one of the targets of petroleum refiners to achieve a clean and safe environment. We report in this study a series of CeOx–Si–CoMo catalysts for the efficient HDS activity of DBT in a batch reactor. The dispersion and catalytic activity of the active species (CoMoS) is greatly influenced by the CeOx–Si network in the support, and the structural reactivities of the catalysts are extensively studied. The BET surface area, X-ray diffraction (XRD) and Raman spectroscopy results showed that up to 2.5 wt% Ce incorporated into the silica network of SBA-15 demonstrated the optimum support properties. The ease of metal oxide reducibility and the existence of the MoS2 phase in the sulfided 2.5CeOx–Si–CoMo catalyst revealed that moderate metal–support interactions between the active metals and the supports are achieved at 2.5 wt% ceria, which resulted in higher HDS activity. The HDS and hydrogenation (HYD) rate constants for the 2.5CeOx–Si–CoMo catalyst were the largest compared to the rate constants of other catalysts, indicating higher catalytic activity. The 2.5CeOx–Si–CoMo catalyst directed the HDS reaction towards the HYD pathway more than the other catalysts.