Co Migration-Guided Reconstruction of Active Phases for Enhanced Hydrodenitrogenation Selectivity

The core of developing highly active Co(Ni)Mo(W)-based hydrogenation catalysts lies in enhancing the accessibility of edge sulfur vacancies. In CoW-supported catalysts, the formation of separate CoSx species often weakens the synergistic effect between Co and W species. This study proposes a strategy of “additive introduction–hydrothermal treatment” to induce active-phase reconstruction. This approach not only promotes the migration of Co species to the edges of the WS2 stacking structure, facilitating the formation of highly active CoWS phases (the CO-IR peak integral area of CoW@A-1 is 3.2 times that of the reference sample CoW@A-4), but also optimizes the stacking structure, increasing the WS2 dispersion (fW) from 0.25 to 0.32, thereby enhancing rim sites with hydrogenation activity and reducing the proportion of inert basal planes. Consequently, the hydrodenitrogenation (HDN) conversion of CoW@A-1 is 26.9%–43.5% higher than that of CoW@A-4. Furthermore, the content of the denitrogenation product propylcyclohexane (PCH) generated via the decahydroquinoline (DHQ) pathway in the product of the CoW@A-1 catalyst reached 2.9 times that of the CoW@A-4 catalyst. This work overcomes the limitations of conventional stepwise regulation strategies, providing a novel design strategy for efficient HDN catalysts.