Cu-Mn-Ce/γ-Al_2O_3汽车尾气净化催化材料的合成及性能的研究

Synthesis and Catalytic Property of Cu-Mn-Ce/γ-Al_2O_3 Complex Oxide

采用固定床反应装置,模拟汽车尾气的组成成分,以CO氧化和NH3选择还原NO为探针反应,研究了焙烧温度和焙烧时间等因素对复合金属氧化物催化材料Cu Mn Ce O γ Al2O3的催化活性的影响,并考察了该催化剂的抗硫化中毒性能。在本研究条件下,焙烧温度在700℃左右,焙烧时间为2.5h时,催化剂对NO CO体系中CO的氧化率在76%以上,对NH3 NO体系中的NO的最佳催化还原率在80%以上。催化剂在3.0%SO2 空气气氛中强制中毒后,其在NH3 NO气氛中的最佳反应温度～450℃,同样条件下未中毒催化剂的最佳反应温度为350℃左右,并且催化剂中毒后对NO NH3的最大转化率没有下降,但是对NO CO体系的反应活性明显下降,说明该催化剂具有良好的高温活性和抗硫中毒性能。

A new type of catalytic material for purification of automobile exhaust Cu-Mn-CeO/γ-Al_2O_3 was studied. The factors affecting its catalytic activity, such as calcination temperature and the period of calcinations and so on were investigated. Its catalytic activity after SO_2-poisoning was determined in a fixed-bed reactor by exposing the sample to the atmosphere of 160 ml·min^(-1) SO_2/air. The study reveals that the catalyst shows high catalytic activities for the conversion of NH_3 oxidation by NO after sulphidisation. The conversion of NO reduction over the suliphidised catalyst is somewhat higher than that over the fresh catalyst except that the optimum temperature increases about 100 ℃. Also at the optimum process for the experiment, the selective catalytic oxidation of CO by NO is over 76% and the conversion of NO reduction is over 80% by NH_3.