CoMo/Al2O3 hydrotreating catalysts of diesel fuel with improved hydrodenitrogenation activity

The possibility to increase the activity of CoMo/Al2O3 catalysts in the desulfurization and denitrogenation of diesel fuel by introducing different amounts of phosphorus is studied. Phosphorus content in the catalysts was adjusted by addition of various amounts of H3PO4 to the impregnating solution containing Co, Mo and citric acid. CoMo with 1 wt.% of P and 1 wt.% of B was also investigated. Catalysts were characterized by HCNS-analysis, nitrogen adsorption, XPS, HRTEM, UV-vis DRS and IR-spectroscopy of adsorbed CO. Catalysts were tested in hydrotreating of straight-run diesel fuel. It was found that the morphology and dispersion of the sulfide active component was independent to the phosphorus content in catalysts. Amount of CoMoS phase increased in catalysts, while the concentration of the surface P-OH groups and Lewis acid sites decreased. The catalyst with 1 wt.% of P and 1 wt.% of B had a maximal activity in desulfurization and denitrogenation reactions. (c) 2017 Elsevier B.V. All rights reserved.