Abstract: A novel hydrothermal deposition method for preparing the highly dispersed W/Al2O3 hydrodesulfurization catalyst was developed and compared with the conventional impregnation method. By the hydrothermal deposition method, WO3 was deposited on the γ-Al2O3 support via the precipitation reaction of sodium tungstate and hydrochloric acid under hydrothermal conditions. A cation surfactant hexadecyltrimethylammoni-um bromide (CTABr) was used in the hydrothermal deposition process to prevent the aggregation of WO3 particles. The catalyst was characterized by X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, N2 adsorption, and temperature-programmed reduction. The catalyst activity was tested using hydrodesulfurization of dibenzothiophene. The results showed that compared with the catalyst prepared by the impregnation method, the catalyst with the same metal content prepared by the hydrothermal deposition method had higher dispersion of tungsten species, larger specific surface area and pore volume, weaker metal-support interaction, and shorter length and higher stacking of WS2 slabs. As a result, the activity of the catalyst prepared by hydrothermal deposition was 15%-18% higher than that of the catalyst prepared by the impregnation method. The high dispersion of tungsten species and the weak interaction between tungsten species and alumina in the catalyst prepared by hydrothermal deposition should be attributed to the low diffusion resistance of the hydrothermal solution and the structural stabilization effect of the surfactant CTABr.

Key words: hydrothermal deposition, tungsten, alumina, dibenzothiophene, hydrodesulfurization, high dispersion, weak interaction