锆含量对（CeMn）1-xZrxO2催化剂催化燃烧碳烟稳定性能的影响

采用共沉淀法制备了系列(CeMn)1-xZrxO2n(CeO2)∶n(MnO2)=6∶4,0≤x≤0.3]催化剂并进行了表征.考察了该系列催化剂对柴油车排放碳烟的催化燃烧性能.X射线衍射和低温氮气吸附-脱附结果表明,向CeMnO2催化剂中引入ZrO2后可以有效稳定催化剂的结构性能和织构性能,当x≥0.2时对结构性能的稳定效果最佳,当x≥0.1时对织构性能稳定效果最佳.氢气-程序升温还原(H2-TPR)结果表明,加入ZrO2后稳定了老化催化剂的低温还原性能,当x=0.2时老化催化剂的低温还原性能最优.氧气-程序升温脱附(O2-TPD)结果表明,加入ZrO2后增加了催化剂表面的阴离子空位,使其吸附和活化氧的能力增强.活性测试结果表明,该系列新鲜催化剂用于碳烟的催化燃烧可有效降低碳烟在燃烧过程中失重速率最大时对应的温度(Tm)约270℃,老化后引入锆的催化剂的稳定性能明显优于无锆催化剂,当x=0.2时催化剂的抗老化性能最佳,于700℃老化20 h前后Tm的差仅有6℃.

Influence of Zr Content on Stability of （CeMn）1-xZrxO2 Catalysts for Catalytic Combustion of Diesel Soot

(CeMn)1-xZrxO2 catalysts were prepared by co-precipitation, where 0≤x≤0.3 and the molar ratio of CeO2 to MnO2 was 6: 4. The catalytic activities of these catalysts for the catalytic combustion of diesel soot were investigated. The catalysts were further characterized by a series of characterization methods. The results of X-ray diffraction(XRD) and low temperature nitrogen adsorption-desorption measurements indicated that the addition of ZrO2 improved the structure properties and textural properties of aged catalysts. When x≥0.2, the catalysts exhibited optimum structure properties, while improved textural properties could be observed for the catalysts with x≥0.1. The results of H2-temperature programmed reduction(H2-TPR) measurements revealed that, among the ZrO2-doped aged catalysts, the one with x=0.2 exhibited the best low-temperature reduction ability. The results of O2-temperature programmed desorption(O2-TPD) measurements suggested that the adding of ZrO2 increased the anion vacant sites on the surface of the catalysts and improved the catalyst's ability to adsorb and activate O2. The results of catalytic activities of these catalysts discolsed that Tm(Tm is the temperature at which the maximal mass loss can be observed in the combustion process of soot) of the fresh catalysts decreased by about 270 ℃. After aged, the adding of ZrO2 increased the stability. When x=0.2, the catalyst exhibited excellent thermal resistance performance, the gap of Tm before and after aging was only 6 ℃. These catalysts suggested potential application in diesel soot catalytic combustion.