Effect of preparation methods on the hydrocracking performance of NiMo/Al2O3 catalysts

• 机 构: Key Laboratory of Oil & Gas Fine Chemicals, Ministry of Education, College of Chemistry and Chem
• 出 处: null
• 发表日期: 2021年04期
• 基金项目: Financial support from the National Natural Science Foundation of China （21968034）；

In this work, NiMo catalysts with various contents of MoO3 were prepared through incipient wetness impregnation by a two-step method（NM-x A） and one-pot method（NM-xB）. The catalysts were then characterized by XRD, XPS, NH3-TPD, H2-TPR, HR-TEM, and N2 adsorption–desorption technologies.The performance of the NiMo/Al2O3 catalysts was investigated by hydrocracking low-temperature coal tar. When the MoO3 content was 15 wt%, the interaction between Ni species and Al2O3 on the NM-15 B catalyst was stronger than that on the NM-15 A catalyst, resulting in the poor performance of the former.When the MoO3 content was 20 wt%, MoO3 agglomerated on the surface of the NM-20 A catalyst, leading to decreased number of active sites and specific surface area and reduced catalytic performance. The increase in the number of MoS2 stack layers strengthened the interaction between Ni and Mo species of the NM-20 B catalyst and consequently improved its catalytic performance. When the MoO3 content reached 25 wt%, the active metals agglomerated on the surface of the NiMo catalysts, thereby directly decreasing the number of active sites. In conclusion, the two-step method is suitable for preparing catalysts with large pore diameter and low MoO3 content loading, and the one-pot method is more appropriate for preparing catalysts with large specific surface area and high MoO3 content. Moreover, the NMx A catalysts had larger average pore diameter than the NM-xB catalysts and exhibited improved desulfurization performance.