Design of active phase structure with high activity and stability in residue hydrotreating reactions

The catalyst with well-dispersed (Ni)MoS2 active phase characteristic of short slab length and low stacking numbers was designed by strengthening metal-support interaction (MSI) and metal dispersion, which displayed high activity and long-term stability in real-life residue hydrodesulfurization (HDS) reactions. Furthermore, the impacts of pseudo-boehmite and catalyst calcination temperature on surface properties were thoroughly investigated. Mo equilibrium adsorption method, Al27 NMR, XRD, Raman, UV–Vis DRS, and H2-TPR characterization showed that the hydroxyl groups concentration and tetrahedral cation vacancies increased upon reducing the pseudo-boehmite extrudates calcination temperature. Increasing calcination temperature of the catalysts further strengthened MSI, resulted in well-dispersed Mo species with enhanced MSI. Therefore, well-dispersed (Ni)MoS2 active phase was acquired on novel designed catalyst. XPS coupled with HRTEM indicated that the more potential active sites, less propensity for active phase evolution and gradual increase in sulfidation degree with processing time contributed to the high HDS performance of the designed active phase. This work can deepen our understanding toward evolution pattern of active phase during residue HDS catalysts, and give guidance for developing high performance catalyst by strengthening MSI and enhancing metal dispersion.