Papadopoulou Ch, Vakros J, Matralis H K, Kordulis Ch, Lycourghiotis A
Department of Chemistry, University of Patras, and Institute of Chemical Engineering & High Temperature Chemical Processes (ICE/HT), PO Box 1414, GR-265 00 Patras, Greece.
J Colloid Interface Sci. 2003 May 1;261(1):146-53. doi: 10.1016/s0021-9797(02)00167-4.
A series of CoMo/gamma-Al(2)O(3) catalysts have been prepared using various methodologies. One of them (EDF) was prepared by depositing the Mo species on the support via the equilibrium deposition filtration (EDF) technique and then the Co species by dry impregnation. Another catalyst (co-EDF) was prepared by depositing the Co and Mo species simultaneously via EDF. A third catalyst (co-WET) was prepared by depositing Mo and Co species simultaneously using the wet impregnation method. The fourth catalyst (WET) was prepared by depositing the Mo species through wet impregnation and then the Co species by dry impregnation. Finally, the fifth catalyst (s-DRY) was prepared by mounting the Mo species through successive dry impregnations and then the Co species by dry impregnation. In all cases the Mo and Co content was identical, giving a Co/(Co+Mo) ratio equal to 0.13. These catalysts were characterized using various physicochemical techniques (BET, NO chemisorption, DRS, LRS, TPR, and XPS), and their catalytic activity for the hydrodesulfurization of thiophene was determined. The trend observed for the HDS activity (namely, EDF>co-EDF>co-WET>s-DRY>WET) is attributed to similar trends observed for both the fraction of well-dispersed octahedral cobalt in the oxidic precursors and the concentration of the edge sulfur vacancies formed on the active phase of the sulfided samples. The EDF and co-EDF catalysts exhibited relatively low hydrogenating activity. The maximum HDS activity, achieved over the EDF catalyst, suggested the most suitable preparative strategy for the preparation of very active and less hydrogen-demanding CoMo/gamma-Al(2)O(3) HDS catalysts.
采用多种方法制备了一系列CoMo/γ-Al₂O₃催化剂。其中一种（EDF）是通过平衡沉积过滤（EDF）技术将钼物种沉积在载体上，然后通过干浸渍法沉积钴物种。另一种催化剂（co-EDF）是通过EDF同时沉积钴和钼物种制备的。第三种催化剂（co-WET）是通过湿浸渍法同时沉积钼和钴物种制备的。第四种催化剂（WET）是通过湿浸渍法沉积钼物种，然后通过干浸渍法沉积钴物种制备的。最后，第五种催化剂（s-DRY）是通过连续干浸渍法负载钼物种，然后通过干浸渍法负载钴物种制备的。在所有情况下，钼和钴的含量相同，Co/(Co+Mo)比等于0.13。使用各种物理化学技术（BET、NO化学吸附、DRS、LRS、TPR和XPS）对这些催化剂进行了表征，并测定了它们对噻吩加氢脱硫的催化活性。观察到的HDS活性趋势（即EDF>co-EDF>co-WET>s-DRY>WET）归因于在氧化前驱体中八面体钴的良好分散分数以及在硫化样品活性相上形成的边缘硫空位浓度所观察到的类似趋势。EDF和co-EDF催化剂表现出相对较低的加氢活性。在EDF催化剂上实现的最大HDS活性表明，这是制备非常活性且对氢需求较少的CoMo/γ-Al₂O₃ HDS催化剂的最合适制备策略。
