铈基和镧基复合氧化物催化剂催化碳烟燃烧性能研究

Study on the Catalytic Soot Combustion Properties of Cerium-and Lanthanum-Based Composite Oxide Catalysts

文章采用浸渍法、水热合成法和共沉淀法制备了3种不同类型的碳烟催化剂:CeFeCo、La-Mn-O和BiCeO。通过对3种样品扫描电镜(SEM)、X射线衍射(XRD)、X射线电子能谱(XPS)和氢气程序升温还原(TPR)等表征结果进行比较分析,发现:La-Mn-O样品中吸附氧的占比量最大;CeFeCo样品中的金属离子含量最多,且Ce^(3+)含量大于BiCeO样品。在氢气程序升温还原中,可以观察到CeFeCo具有最低温的还原峰,在283℃左右。最后通过程序升温氧化反应系统对3个样品进行活性评估,在紧密接触情况下CeFeCo、La-Mn-O和BiCeO样品催化50%碳烟氧化所需的温度,即T_(50)分别为329、355和374℃,与碳烟燃烧的空白组相比,T_(50)分别降低了265、239和220℃。这表明3种催化剂均成功制备并且具有良好的催化碳烟燃烧性能,特别是CeFeCo催化剂表现出的低温催化燃烧性能最好。

Three different types of carbon soot catalysts,CeFeCo,La-Mn-O and BiCeO,were prepared by impregnation,hydrothermal synthesis and co-precipitation methods.By comparing and analyzing the characterization results of the three samples,such as scanning electron microscopy(SEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS) and H_(2)-temperature programmed reduction(TPR),it can be found that La-Mn-O sample has the largest proportion of chemisorbed oxygen,CeFeCo sample has the largest metal ion content,and Ce^(3+) content is higher than BiCeO sample.It can be found that CeFeCo has the lowest reduction peak at about 283 ℃ in the H2-TPR.Finally,the activities of the three samples were evaluated by a temperature-programmed oxidation reaction system.The temperatures required to catalyze the oxidation of 50% soot for CeFeCo,La-Mn-O and BiCeO samples in tight contact were 329,355 and 374 ℃,respectively,which were reduced by 265,239 and 220 ℃,compared with the blank group.This indicates that all three catalysts were successfully prepared and had good catalytic soot combustion performance,and especially the CeFeCo catalyst exhibited the best low-temperature catalytic combustion performance.