The Formation of the Active Phases in Sulfided NiW/Al_2O_3 Catalysts and Their Evolution during Post-Reduction Treatment

摘要

From the activity measurements of NiW/Al_2O_3 catalysts in the HDS reactions of thiophene and 4,6-DMDBT and their characterization results, we can conclude that the significant increase in catalytic activity with the addition of Ni is related to the family of highly active NiWS phase, the amount of which is proportional to the concentration of Ni up to Ni/(Ni+W) = 0.41. The slight increases of the dispersion of WS_2 phase and of the amount of W~(Ⅵ) species (i.e., sulfiding degree) are also beneficial to providing more edge sites for the formation of NiWS phase.