RuS2-modified NiW/Al2O3 catalysts for refractory 4,6-dimethyl-dibenzothiophene hydrodesulfurization

Al2O3-supported noble metal (NM)-modified hydrodesulfurization (HDS) catalysts (W 15.8 wt% and Ni 3.5 wt%) were applied in refractory 4.6-dimethyl-dibenzothiophene elimination. Corresponding Ru-doped (0.5 and 0.7 wt %) materials were either dried (120 degrees C) or dried followed by calcining (400 degrees C) after NM deposition prior to activation (400 degrees C, 15/85H(2)S/H-2 mixture). In solid at 0.5 wt% NM calcined after Ru deposition ruthenium was less dispersed (XRD and TPR) than over corresponding just dried one. Also, WS2 had higher dispersion (HR-TEM) on the latter. However, NiWS phase was enhanced (XPS) on the former material. NM-doped catalysts annealed before activation showed significantly enhanced activity (x2.4 and x1.6, solids with 0.5 and 0.7 wt% Ru, respectively) in refractory dibenzothiophene (DBT) HDS, as to that of pristine NiW/Al2O3. Enhanced hydrogenating properties of the former materials improved S elimination from sterically-hindered DBT. Conversely, Rudoping was detrimental on NiW/alumina when non-annealed prior to activation. Unreduced Run+ and decreased pyrite-like RuS2 species (XPS) on those catalysts could be related to their strongly diminished HDS activity.

Automated summary

In this study, researchers successfully achieved deep removal of refractory dibenzothiophene using catalysts supported on Al2O3 with noble metal modification. Calcined catalysts showed better catalytic activity, while Ru-doped catalysts were detrimental to catalytic activity when not calcined before activation.