柠檬酸与磷的改性对Ni-Mo/Al2O3焦化蜡油加氢脱氮性能的影响

以γ-Al₂O₃为载体，Ni-Mo为活性金属组分，采用等体积溶液浸渍法制备了焦化蜡油加氢处理催化剂Ni-Mo/Al₂O₃。在浸渍液中分别加入柠檬酸、磷酸二氢铵，以及同时加入柠檬酸和磷酸二氢铵，得到改性的催化剂Ni-Mo-CA/Al₂O₃、Ni-Mo-P/Al₂O₃和Ni-Mo-P-CA/Al₂O₃，采用NH₃-TPD、H₂-TPR、UV-Vis DRS和HRTEM等手段对制备的催化剂进行了表征，考察了柠檬酸和磷改性对催化剂的性质和加氢脱氮活性的影响。结果表明，磷改性提高了Ni-Mo/Al₂O₃催化剂的表面酸量，但降低了其加氢脱氮活性；柠檬酸的改性提高了Ni-Mo/Al₂O₃催化剂的加氢脱氮活性，但降低了催化剂的表面酸量；柠檬酸 磷的组合改性使Ni-Mo/Al₂O₃催化剂同时具有较高的表面酸量和加氢脱氮活性。柠檬酸-磷的组合改性使Ni-Mo/Al₂O₃催化剂的表面形成了更多的高活性Mo物种，活性金属有着更高的分散性，MoS₂堆垛层数集中分布在2层和3层，从而使其对焦化蜡油的加氢脱氮活性得到了大幅提升。

Effect of the Modification by Citric Acid Cooperating With Phosphorus on the Hydrodenitrogenation Performance of Ni-Mo/Al2O3 for Coking Gas Oil

Ni-Mo/Al₂O₃ catalysts for coking gas oil (CGO) hydrodenitrogenation were prepared by incipient wetness impregnation method with Ni and Mo as active metals and γ-Al₂O₃ as support. The Ni-Mo/Al₂O₃catalyst was modified by ammonium dihydrogen phosphate, citric acid and ammonium dihydrogen phosphate cooperating with citric acid during impregnation, respectively. The modified Ni-Mo/Al₂O₃catalysts were named as Ni-Mo-P/Al₂O₃, Ni-Mo-CA/Al₂O₃ and Ni-Mo-P-CA/Al₂O₃catalysts, respectively, and their catalytic performances for coking gas oil hydrodenitrogenation(HDN) were examined. The physical and chemical properties of these catalysts were investigated by NH₃-TPD, H₂-TPR, UV-Vis DRS and HRTEM. The results indicated that on the surface of Ni-Mo-P/Al₂O₃ catalyst the amount of acid was increased and the HDN activity was weakened, while on the surface of Ni-Mo-CA/Al₂O₃ catalyst the amount of acid was decreased and the HDN activity was strengthened, compared with unmodifiedNi-Mo/Al₂O₃ On the surface of Ni-Mo-P-CA/Al₂O₃ catalyst both the amount of acid increased and HDN activity was remarkably promoted, because more Mo species of high activity were formed, the dispersion of active components was increased and most of MoS₂ nanoparticles were dilayered and trilayered.