Relation between the morphology of MoS₂ in NiMo catalyst and its selectivity for dibenzothiophene hydrodesulfurization

 Two series of NiMo catalysts supported on alumina with different loadings of molybdenum and nickel were prepared and characterized by X-ray diffraction, N₂ sorption, and high-resolution transmission electron microscopy. The performance of NiMo catalysts for hydrodesulfurization was evaluated in a fixed-bed microreactor using dibenzothiophene as a model compound. The effect of morphology of MoS₂ phase in NiMo catalyst on its hydrogenation selectivity was investigated. The results indicated that the morphology of MoS₂ phases is affected by the loadings of molybdenum and nickel. Mo18Ni4 catalyst (containing 18% MoO₃ and 4% NiO), which is provided with the well-known MoS₂ slab structures with a multilayered morphology, exhibits high hydrodesulfurization activity and hydrogenation selectivity. The hydrogenation selectivity of NiMo catalyst is linearly correlated with the stacking number of MoS₂ slab; the higher the stacking number, the better is the hydrodesulfurization selectivity.