关键词: Fe改性, 表面元素, 活性金属, 自组装, 催化剂

Abstract:

The hydrogenation catalysts with Mo and Ni as active centers were modified with macroporous nano?alumina as carrier and iron as auxiliary agent, and Fe?Mo?Ni and Fe?Ni catalysts were prepared by secondary nano?self?assembly method respectively. The experimental results show that the iron modified catalysts MNF?70C and NF?70C have bimodal pore structure, the larger most probable pore diameter is 50.0 nm and 40.0 nm respectively, and the smaller most probable pore diameter is 5.5 nm. It can be seen that under the action of complexing agent and promoter Fe, Fe, Mo and Ni in MNF?70C catalyst form a large number of nano self?assemblies in the form of metal bonds on the inner and outer surfaces of macroporous alumina, which are more evenly dispersed and have more pores suitable for hydrogenation reaction. The pore size distribution of MNF?70C and NF?70C catalysts in the range of 6.0~60.0 nm reached 78.05% and 72.80% respectively. It shows that the addition of structural assistant iron improves the dispersion of active metals, so as to effectively improve the pore size distribution of the catalyst. The characterization analysis of CO adsorption, H₂?TPR TEM and XPS further shows that the Fe modified catalyst has linear adsorption for CO, its reduction temperature is low, and it has been evenly dispersed in the form of nanoparticles, with more catalytic active centers, indicating that this kind of catalyst has better hydrogenation catalytic activity. Because Fe is cheap, the addition of additives can improve the quality of the oil after hydrogenation or reduce the amount of catalyst active metal, so as to reduce the cost of synthetic catalyst, which is suitable for the development of heavy oil hydrogenation catalyst for industrial application.

Key words: Iron modified, Surface element content, Reactive alloys, Self?assembly, Catalysts