Regresar

First-principles study of the nature of niobium sulfide catalyst for hydrodesulfurization in hydrotreating conditions

Abstract:

For the metal-edge of pure NbS2 catalyst mixed with Mo and promoted with V, Fe, Co, and Ni, density functional theory and first-principles surface thermodynamics calculations at hydrodesulfurization conditions have been performed. It was found that V, Co, and Ni promoters impart stabilization to the catalyst surfaces whereas Fe produces an opposite effect and renders the catalysts less stable. Catalyst structures corresponding to the fully Ni-promoted edge of the mixed Mo-Nb sulfide with a Mo3Nb2S10 composition and to the NbS2 V-promoted with 50% sulfur coverage forming S dimers are by far the most stable structures. The nature of the hydrodesulfurization active sites of both most stable monolayers were studied using reactivity pbkp_redictors such as the electrostatic potential, the electronic localization function, and the Laplacian of the electronic density.