以硫化态前驱物制备的NiMoS/γ-Al_2O_3催化剂表面活性相HRTEM研究

INVESTIGATION OF ACTIVE PHASE OF NiMoS/γ-Al_2O_3 PREPARED BY THIOSALT AS PRECURSOR THROUGH HRTEM

采用硫化态前驱物四硫代钼酸铵溶液浸渍载体γ-Al2O3制备了硫化态NiMoS/γ-Al2O3加氢精制催化剂,对催化剂进行了XRD和HRTEM表征,并以FCC柴油为原料,考察了催化剂的加氢精制性能。结果表明,该加氢催化剂的活性组分与载体γ-Al2O3的相互作用较弱,不存在难以还原硫化的Mo—O—Al桥键,催化剂表面MoS2分散度较好,MoS2的晶粒较大,堆积层数较高,大部分MoS2以Ⅱ型的NiMoS相存在;硫化态NiMoS/γ-Al2O3加氢精制催化剂具有优于工业催化剂CK-2的脱硫、脱氮和脱芳烃性能。

Sulfide NiMoS/γ-Al2O3 hydrotreating catalyst was prepared through impregnating sulfide precursor ammonium tetrathiomolybdate aqua solution into carrier γ-Al2O3 and the catalyst was investigated by means of XRD and high resolution electron microscopy （HRTEM） to get a better understanding of the nature of the active phase. The hydrotreating performance of the catalyst was evaluated with the FCC gas oil as the feed. The results of XRD and HRTEM characterizations indicated that interaction between active components and carrier γ-Al2O3 was weaker through sulfide precursor （ATTM） than that through oxidation precursor, the catalyst prepared by this method could not come into being Mo--O--Al anchors, which were difficult to be reduce-sulfided. The dispersion of MoS2 on NiMoS/γ-Al2O3 catalyst surface was well, and the slab size of MoS2 on NiMoS/γ-Al2O3 surface was bigger and the stacking degree of MoS2 was higher than that on the surface of CK-2, a commercial catalyst, and those MoS2 presented in type Ⅱ NiMoS active phase in a great measure. The evaluation results of FCC gas oil hydrotreating experiment indicated that the performance of sulfide NiMoS/γ-Al2O3 hydrotreating catalyst was a little better than that of commercial catalyst CK-2.