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采用程序升温还原(TPR)、高分辨透射电镜(HRTEM)和X射线光电子能谱(XPS)表征手段对共浸渍法制备的不同磷含量NiMo/γ-Al_2O_3催化剂进行了表征,研究了磷含量对NiMo/γ-Al_2O_3催化剂活性相结构的影响.TPR研究表明,磷能够减少四面体配位Mo物种的数量,增加八面体配位Mo物种的数量,促进高活性Ⅱ型“Ni-Mo-S”活性相的形成.HRTEM研究表明,随磷含量的增加,MoS_2颗粒堆积层数增加,催化剂的加氢选择性提高;适量磷能够增加边角位有效Mo原子的分散度(f_(Mo)),增加催化剂表面加氢脱硫(HDS)和加氢脱氮(HDN)活性位的数量.上述结论得到了XPS表征的证实:适量磷增加了催化剂表面Mo原子浓度、提高有效助剂比率(PR)和提升比率(Ni/Mo),相应催化剂表现出最高的HDS和HDN活性;但过高磷含量能够引起MoS_2颗粒过度堆积,片层长度过长,导致活性位数量减少,催化活性降低.“,”NiMoP/Al_2O_3 catalysts with different phosphorus contents were prepared by co-impregnation method and characterized by temperature-programmed reduction (TPR), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) tests. The effect of phosphorus content on the active phase structure of these catalysts was investigated. The TPR results indicated that with the increase of the phosphorus content in the catalysts, the amount of tetrahedral Mo species was decreased, while that of octahedral Mo species was increased. The HRTEM results showed that the number of stacking layers of MoS_2 nanoparticles increased with the phosphorus content, which was effective to enhance the hydrogenation selectivity of the catalysts. The fraction of available Mo dispersion (f_(Mo)) and the number of active phases in the catalysts increased with increasing phosphorus content to P/MoO_3 = 0.09; beyond that, a reverse trend was observed. High HDS and HDN activity were obtained over the catalyst with the phosphorus content of P/MoO_3 = 0.09, which could be attributed to its high concentration of Mo atoms on the catalyst surface, high efficient promotion rate (PR) and high promoter ratio (Ni/Mo). However, excessive phosphorus content may deteriorate the performance of NiMoP/Al_2O_3 catalysts due to the aggregation of active components.