LAUSR

NiMo/alumina catalysts were prepared by impregnation of metal precursors in the presence of citric acid (CA) at different pHs. Catalysts were characterized by nitrogen physisorption, X-ray diffraction, temperature programmed reduction of sulfided catalysts (TPR-S), temperature programmed sulfidation (TPS) and NO chemisorption of sulfided catalysts. Catalytic activity for dibenzothiophene (DBT) hydrodesulfurization (HDS) was studied in a trickle-bed reactor, with and without quinoline in the reaction feed. Results suggest that HDS of DBT occurs mainly by direct desulfurization route and CA addition at pH 3 was detrimental, resulting in a less active catalyst, which was confirmed by TOF calculations. Furthermore, TPR-S results show that the catalyst prepared at pH 3 presented less coordinatively unsaturated sites (CUS), being less active than the one synthesized at pH 1. Besides that, the catalyst prepared at pH 1 was less inhibited at higher quinoline concentrations.Graphical Abstract