Insights into the hydrodesulfurization reaction mechanisms catalyzed by different K-promoted MoS2 edge sites

Abstract

The K-promoted MoS2 active phase structure and its catalytic mechanism in the hydrodesulfurization reaction were investigated through the density functional theory calculations. On the basis of the calculations, the sulfur vacancy formation mechanism and the direct desulfurization of thiophene were systematically explored, and the structure–activity relationship was also discussed in detail. In the sulfur vacancy generation process, it could be found that the formation of sulfur vacancies was more favorable over the sulfur-rich edges, such as K-promoted S-edge with 100 % S coverage. In addition, the K-promoted S-edge was more preferable for the C-S bond scissions compared with the K-promoted M−edge. Furthermore, potassium atoms could prevent the adsorptions of toluene and 2-butene adsorptions, in order to reduce the excessive hydrogenation saturation of olefins and monocyclic aromatics, which would be beneficial for the octane rating maintenance during the production process of gasoline.