Hydrodesulfurization of dibenzothiophene over tungsten phosphide loaded on AlMCM-41 containing aluminophosphate building units

As a support, AlMCM-41 containing aluminophosphate building units with different Si/Al molar ratio(Si/Al=30, 40, 50, 55, 60, respectively) was synthesized by microwave heating method. The supported tungsten phosphide(WP) catalysts with different Si/Al molar ratio were prepared by impregnation and H₂-TPR(temperature programed reduction in hydrogen flow)method. The samples were characterized by X-ray diffraction (XRD), BET specific surface area, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) methods. The dibenzothiophene (DBT) hydrodesulfurization (HDS) activities of the catalysts were evaluated by a fixed-bed micro-reactor. Active species of WP and the structure of -Al-O-W-P, the matter with some activity, were detected on the catalysts surface. WP was the dominative active phase. The percentage of active phase WP on the catalyst surface was influenced by the Si/Al molar ratio. Catalysts with different Si/Al molar ratio exhibited different selective hydrogenation performances, and direct hydrodesulfurization(DDS) was the main DTB HDS route. Catalyst with Si/Al molar ratio of 55 was found to give a higher DDS products (PB) selectivity of 82.7% and a higher DBT HDS conversion of 93.1%, which was favor to reducing the hydrogen consumption and protecting the environment.