Effect of Ni loading and impregnation method on the hydrodenitrogenation of coal tar over Ni-Mo/γ-Al2O3

Ni-Mo/γ-Al2O3 catalysts with different Ni loadings were prepared. They were characterized by X-ray diffraction (XRD), N2 adsorption, IR spectra of adsorbed pyridine (Py-IR), temperature-programmed desorption of ammonia (NH3-TPD), temperature-programmed reduction of H2 (H2-TPR), and high resolution transmission electron microscopy (HRTEM). The hydrodenitrogenation (HDN) performance of catalysts for coal tar were evaluated. The best hydrodenitrogenation activity was observed on the catalysts with a Ni loading of 6.25 wt% and a Ni/(Ni+Mo) ratio of 0.4. Also, the methods of co-impregnation and sequence-impregnation were compared. The denitrification rate of co-impregnation catalyst NiMo-5-co (71.2%) was slightly lower than that of sequence-impregnation catalyst NiMo-5 (71.7%). Disparate product distribution was obtained on NiMo-5-co and NiMo-5. The dispersion of active components, the distribution of pore and acid on catalysts played an important role in HDN process of coal tar.