A novel strategy for preparing NiMo/SiO2-Al2O3 ultra-deep hydrodesulfurization (HDS) catalysts through gemini surfactant-assisted synthesis of Mo-based precursors is proposed. The proposed method transforms polymolybdate anions into gemini surfactant-linked Mo-based precursors, promoting the dispersion of Mo species. The catalysts were characterized by nitrogen adsorption-desorption, X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (UV-DRS), hydrogen temperature-programmed reduction (H2-TPR), high-resolution transmission electron microscope (HRTEM), X-ray photoelectron spectroscopy (XPS), NO-infrared (NO-IR) and tested in the simultaneous HDS of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and FCC diesel. Nitrogen adsorption-desorption and XRD results showed that the prepared catalyst has small MoO3 particles with little influence on the catalyst pore structure. According to the characterization of the prepared catalyst by H2-TPR and UV-DRS, the molybdenum species are mainly attributed to octahedrally coordinated Mo6+ (Oh) and possess weaker interaction between the support than its counterpart prepared via the impregnation method. The weakened interaction increases the stacking number of the MoS2 phases and produces a large number of accessible Ni-Mo-S phases after Ni incorporation which demonstrated by HRTEM, XPS and NO-IR. The prepared catalyst presents higher activity for the direct desulfurization and hydrogenation of sterically hindered 4,6-dimethyldibenzothiophene (4,6-DMDBT) than its counterpart prepared via the impregnation method according to the HDS of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and FCC diesel. This method finely adjusts the morphology of supported Ni-Mo-S phases in HDS catalysts for the ultra-deep HDS of fuel.

Gemini surfactant-assisted synthesis of Mo-based precursors for preparing NiMo/SiO2-Al2O3 hydrodesulfurization catalysts

255th National Meeting (2018)

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