Fabrication of a Mo-based catalyst with high DDS pathway selectivity for hydrodesulfurization of dibenzothiophene

With the trend of heavy and inferior crude oil, the design of hydrodesulfurization (HDS) catalysts with excellent activity and high active metal utilization is an inevitable trend for the upgrading of refining technology. In this study, a highly dispersed Mo catalyst confined within nitrogen-doped porous carbon (xMo@NC) was prepared using an in situ encapsulation-pyrolysis approach and used in the HDS reaction of dibenzothiophene (DBT). The methods of XRD, HRTEM, HAADF-STEM, N₂ physisorption, FT-IR, Raman, and XPS were used to carry out thorough microstructural characterization. The results demonstrated that the Mo species in xMo@NC were highly dispersed, exhibiting superior intrinsic HDS activity compared to MoS₂/NC* catalysts and conventional supported catalyst MoS₂/Al₂O₃. The xMo@NC catalyst exhibited significant direct desulfurization (DDS) pathway in the HDS reaction of DBT. Differential charge density and bader charge suggested that significant electron transfer between the sulfur atom of DBT and the Mo species of xMo@NC, which weakened the CS bond and made it easier to remove sulfur via DDS pathway during the HDS reaction. This work presents a new catalytic material with high intrinsic activity and enhanced DDS desulfurization selectivity, providing fresh perspectives on the creation of high-performance HDS catalysts.