Influences of different phosphorus contents on NiMoP/Al₂O₃ hydrotreating catalysts

NiMoP/Al₂O₃ hydrotreating catalysts with different phosphorus contents were prepared by impregnating NiMoP aqueous solution into γ-Al₂O₃. The hydrodesulfurization （HDS）and hydrodenitrogenation (HDN) performances of the catalysts were evaluated using the model compounds dibenzothiophene and quinoline methylbenzene. The results show that the HDS and HDN performances of the catalysts can be improved by adding moderate quantities of phosphorus in the catalysts, and its performance can be decreased markedly when the catalysts have high phosphorus content. The catalysts were investigated by means of XRD and high-resolution transmission electron microscopy (HRTEM) to get a better understanding of the nature of active. The results of XRD and HRTEM characterizations indicate that the number of stacked layers of active component MoS₂ increases with the increase of the phosphorus content. Because the interaction between active component and carrier γ-Al₂O₃ is weakened by adding phosphorus into the catalysts, the relative content of type-II“Ni-Mo-S”phase is increased.