Preparation and hydrodesulfurization properties of cobalt–molybdenum–phosphorous catalysts for removal of dibenzothiophene

Abstract

In this study, a series of cobalt–molybdenum–phosphorous acid (Co–Mo–P) impregnating solutions with various Co/Mo molar ratios (0.2, 0.25, 0.3, 0.35) were synthesized, and desulfurization catalysts were prepared by mixing the solutions with γ-Al2O3 through an incipient-wetness impregnation method. The Co–Mo–P supported γ-Al2O3 catalysts were tested in the hydrodesulfurization of dibenzothiophene (DBT). The catalysts were characterized by N2 adsorption–desorption isotherms, XRD, py-FT-IR, and HRTEM. Nitrogen adsorption measurements revealed that the as-prepared catalysts possess high specific surface area and appropriate pore size. XRD showed that Co species and Mo species were well dispersed on the surface of γ-Al2O3 with the addition of phosphoric acid. Py-FT-IR showed that the catalyst with a Co/Mo molar ratio of 0.25 exhibited more Lewis and Brønsted acid sites. The stacking number and slab length of MoS2 nanoclusters changed with various Co/Mo molar ratios as revealed by HRTEM. Among the tested catalysts, Co–Mo–P supported γ-Al2O3 with Co/Mo molar ratio of 0.25 exhibited higher activity and selectivity of biphenyl than the other catalysts.