镧氧化物对体相MoP加氢脱氮反应性能的影响

采用共沉淀法制备了体相MoP催化剂和La2O3改性的MoP催化剂，用XRD、N2物理吸附及TEM等手段对催化剂进行表征。以喹啉及其加氢中间体十氢喹啉（DHQ）为模型含氮化合物，研究了这些催化剂的加氢脱氮反应性能。结果表明，La2O3是MoP催化剂的有效助剂，同时促进了MoP的加氢活性和C-N键断裂活性，但抑制了DHQ的脱氢。当La/Mo摩尔比大于02时，增加La2O3含量能够显著提高催化剂的比表面积。La2O3含量过高主要生成LaPO4。La2O3改性的MoP催化剂的活性随La/Mo摩尔比增加而增加。当La/Mo摩尔比大于03（催化剂记为La MoP(03)）时，继续增加La2O3含量对催化剂活性影响不大。La MoP(03)中活性相分散度高于MoP催化剂，并且活性相主要呈棒状，不同于MoP催化剂的卵石状。催化剂的性能与其比表面积或分散度之间没有直接联系。喹啉在这些催化剂上主要通过DHQ路径脱氮，引入La2O3对喹啉HDN反应的促进作用比对DHQ的HDN反应更为显著。

Influence of Lanthanum Oxide on the Hydrodenitrogenation Performance of Bulk MoP

Bulk MoP and La2O3 modified MoP catalysts were prepared by a co precipitation method, and characterized by XRD and N2 physisorption methods. The hydrodenitrogenation (HDN) performances of the catalysts were studied using quinoline and decahydroquinoline (DHQ) as the model nitrogen containing compounds. The results indicate that La2O3 is an effective promoter for the MoP HDN catalyst. It enhances both the hydrogenation activity and the C-N bond cleavage activity of MoP but inhibits the dehydrogenation of DHQ. At La/Mo molar ratio above 02, the specific surface area and the dispersion of the catalyst become higher with the increasing of La2O3 content. At high La/Mo molar ratio, LaPO4 is the major phase in the catalyst. Thus, the activity of the catalysts is increasing along with the La/Mo molar ratio. At the La/Mo ratio above 03 (the catalyst is denoted as La MoP(03)), the activity of the catalysts is almost not affected by further increasing the La2O3 content. The dispersion of active phase in La MoP(03) is higher than that of MoP. Rod like and pebble shaped active phases are observed in La MoP(03) and MoP, respectively. There is no relation between the HDN performances and specific surface areas and the dispersions of the La2O3 containing catalysts. The HDN of quinoline over the MoP catalysts occurs mainly through the DHQ pathway, and the HDN of quinoline is significantly enhanced by the addition of La2O3 than the HDN of DHQ.