The Influence of In-modified NiMoS active phase on the direct desulfurization reaction process of 4,6-Dimethyldibenzothiophene

Presently, the number of corner active site of formed NiMoS active phase, which is supported on non-precious metal hydrodesulfurization (HDS) catalyst, is limited and its ductility is poor, greatly reducing direct·desulfurization (DDS) and HDS performances, which brings great challenges to ultra-deep desulfurization. Herein, we used the density functional theory calculation method to explore the effect of single-atom In promoter on geometric and electron structures of active phase, investigated adsorption behaviors of 4,6-dimethyldibenzothiophene (4,6-DMDBT) at different active sites, and thoroughly clarified the effect of these changes on the 4,6-DMDBT DDS pathway. The results indicate that established single-atom In-doped InNiMoS model shown electron-rich characteristic. It was due to strongly s-p-d orbitals interaction of In-Ni atomic pairs loaded at long Mo-edge creating a new active site (E-1) with activity similar to the corner active site. Moreover, doped-In atom at short S-edge improved ductility of the corner active site and effectively increased its geometry space. At the corner active site, first C-S bond cleavage was still rate-controlling step (RCS) of the 4,6-DMDBT DDS, but obtained barriers were different due to the effect of activating H radical by the single-atom In promoter loaded at the short S-edge active site. At the formed E-1 active site of the long Mo-edge active site, the RCS barrier of the 4,6-DMDBT DDS significantly decreased from 201.60 to 140.44 kJ·mol^-1, successfully achieving 4,6-DMDBT DDS conversion.