Insights into the Active Sites of Al2O3-Supported NiMo Catalysts in the Hydrodenitrification Reaction

( )Hydrodenitrification is an important reaction in the petrochemical industry. However, the study of active sites at the atomic scale is still not clear. Herein, sulfurized NiMo/Al2O3 catalysts were prepared and the relationship between the structure and catalytic performance was investigated in detail through many advanced technologies, such as atomic-resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), energy-dispersive spectroscopy elemental mapping, and X-ray photoelectron spectroscopy (XPS). A commercial catalyst C1 showed the highest denitrification percent, and the developed catalyst C2 could also present a catalytic performance comparable to C1 with a lower material cost. HAADF-STEM analysis results showed the catalyst with small MoS2 stack length, and many MoS2 stack layers tended to have high activity due to more active sites being exposed. The S/Mo ratio on the catalyst surface was detected by XPS, and the highest value at 1.92 was obtained for the C1 catalyst, leading to obtaining high activity in the reaction. This work provides fundamental investigation of highly efficient Ni-modified MoS2 catalysts for industrial application at the atomic scale.

Automated summary

This study investigated the relationship between the structure and catalytic performance of sulfurized NiMo/Al2O3 catalysts using advanced technologies, such as HAADF-STEM and XPS. The results showed that catalysts with small MoS2 stack length and many MoS2 stack layers tend to have high activity, and catalysts with a higher S/Mo ratio exhibit higher activity in the reaction.