NiMo/TiO2-Al2O3催化剂活性相表征及加氢脱硫反应性能研究

采用共沉淀法制备TiO₂含量不同的TiO₂-Al₂O₃复合载体，以传统的浸渍法制备活性金属负载量相同的NiMo/TiO₂-Al₂O₃催化剂。运用N₂低温吸附法、X射线衍射、H₂程序升温还原和激光拉曼光谱等方法对催化剂进行表征，在10 mL微型反应装置上进行催化剂活性评价。结果表明，当复合载体中TiO₂含量达到一定值后，TiO₂在整个TiO₂- Al₂O₃体系中的存在状态由高度分散转变为表面富集，XRD能够检测出锐钛矿型TiO₂的特征峰；TiO₂的添加对于催化剂的酸性能没有明显改变；激光拉曼光谱分析结果表明，TiO₂的存在有利于生成八面体结构的钼物种，并在TiO₂质量分数为8%时加氢脱硫活性达到较高水平。

Characterization of active phase of NiMo/TiO2-Al2O3 catalyst and its performance in hydrodesulphurization reaction

TiO2-Al2O3 composite oxide supports with different TiO2 loadings were prepared by coprecipitation method. NiMo/TiO2-Al2O3catalyst with same loadings of active metals was prepared by traditional impregnation method and characterized by BET, XRD, H2-TPR, Laser-Raman spectra techniques. The activity evaluation test of the catalyst was carried out in 10 mL micro-reactor. The results showed that the existing state of TiO2 in TiO2-Al2O3 oxide was changed from high dispersion into the surface enrichment when TiO2 content reached a certain value. The characteristic peaks of anatase titanium dioxide were also detected by XRD. The catalyst acidity had no obvious change by adding TiO2. The results of Laser Raman spectroscopy characterization indicated that the existence of TiO2 was beneficial to forming molybdenum species with octahedral structure. HDS activity of the catalyst with 8% （mass fraction） TiO2 in support reached a higher level.