On the Preferred Active Sites of Promoted MoS₂ for Hydrodesulfurization with Minimal Organonitrogen Inhibition

Abstract

Hydrodesulfurization is a process to produce ultralow-sulfur diesel fuel. Although promoted molybdenum sulfide (MoS2) catalysts have been used industrially for several decades, the active site requirements for selective hydrodesulfurization of organosulfur compounds with minimal inhibition by organonitrogen constituents of a real gasoil feed has not been resolved. Using molecular binding energy descriptors derived from plane wave density functional theory calculations for comparative adsorption of organosulfur and organonitrogen compounds, we analyzed more than 20 potential sites on unpromoted and Ni- and Co-promoted MoS2. We find that hydrogen sulfide and ammonia are simple descriptors of adsorption of sterically unhindered organosulfur and organonitrogen compounds such as dibenzothiophene and acridine, respectively. Further, organonitrogen compounds in gasoil bind more strongly than organosulfur compounds on all sites except on sites with exposed metal atoms on the corner and sulfur edges of promoted MoS2. Consequently, these sites are proposed as required for maximum-hydrodesulfurization minimum-inhibition catalysis.

Transition Metal Dichalcogenides for the Application of Pollution Reduction: A Review

“…Liu et al [215] demonstrated that for a MoS 2 /NiMo catalyst, the higher the number of MoS 2 slabs being stacked, the better the hydrodesulfurization selectivity for DBT. Additionally, Rangarajan et al [216] studied the preferred active sites of a metal-promoted MoS 2 and found that organosulfur and organonitrogen compounds bind weaker on sites with exposed metal on the corner and the sulphur edge of MoS 2 . Hydrodesulfurization of DBT by various morphologies of MoS 2 catalyst was also studied by Tye and Smith [217].…”

Kinetic assessment of the simultaneous hydrodesulfurization of dibenzothiophene and the hydrogenation of diverse polyaromatic structures

“…Under typical sulfidation conditions, nickel atoms might replace the molybdenum atoms from the Mo-edge to form the so-called NiMoS phase and, hence, promote the formation of CUS at the edges and corners due to the reduction of the sulfur binding energy. 75,76 The desulfurization of DBTs via DDS preferably takes place on vacancies at corner sites via perpendicular adsorption through the sulfur atom. 20,24,75,77 On the other hand, the nature of the sites for the HYD pathway is yet unclarified.…”

“…75,76 The desulfurization of DBTs via DDS preferably takes place on vacancies at corner sites via perpendicular adsorption through the sulfur atom. 20,24,75,77 On the other hand, the nature of the sites for the HYD pathway is yet unclarified. Topsøe and coworkers [22][23][24]73 , based on scanning tunneling microscopy (STM) images of the top of MoS2 and CoMoS slabs,…”

The Silicon on the Catalysis: Hydrodesulfurization of Petroleum Fractions

“…The air pollution is one of the main problems that the governments around the world have been concerned to mitigate in recent decades. The harmful gases found in the atmosphere are the product of the generation of energy through the combustion of hydrocarbons [1][2][3]. However, the hydrocarbons will continue to be used as the main source of energy in the next decades [4]; thus, it represents an environmental problem.…”