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.