La_(1-x)Ce_xCu_yMn_(1-y)O_3/HZSM-5催化剂低温去除柴油机碳烟和NO_x

Low-temperature soot and NO_x removal of diesel engine with La_(1-x)Ce_xCu_yMn_(1-y)O_3/HZSM-5 catalyst

为实现对柴油机碳烟和NOx的低温同步去除,采用柠檬酸络合法制备分子筛负载钙钛矿型金属复合氧化物催化剂,应用X衍射分析仪(XRD)和电镜扫描仪(SEM)对催化剂性能进行表征,并在微型固定床反应器中对催化剂低温去除碳烟和NOx进行活性评价。利用程序升温反应(TPR)技术,进行催化剂活性评价、柴油机负荷和排放等特性实验。结果表明,A位用适量Ce部分取代La,B位用适量Cu部分取代Mn,可使碳颗粒燃烧温度降低,CO2选择性好,NOx转化率升高。La0.4Ce0.6Cu0.2Mn0.8O3/HZSM-5催化剂的最大NOx转化率为81.0%,Ti、Tm和Tf分别为250、350和475℃,表明该催化剂具有较好的催化活性,能在低温条件下去除碳烟和NOx。

In order to remove the diesel engine harmful emissions simultaneously on soot and NOx at low temperature,the catalysts of perovskite-type complex oxide loaded on HZSM-5 zeolite were synthesized by the cit- rate complexing method. The catalysts were characterized by XRD and SEM,and their performances for low-tem- perature removing soot and NOx for were evaluated in a fixed micro-reactor. These characteristic tests were carried out on the catalysts active, the load and emissions of the diesel engine by temperature programmed reaction （TPR） method. The results show that A-site parts ion of La was consisted by Ce,and B-site parts ion of Mn was consisted by Cu,the catalyst performances were improved, such as,the soot combustion temperature decreased, the CO2 selectivity and the NOx conversion efficiency increased. To La0 .4 Ce0. 6 Cu0.2 Mn0.8 O3/HZSM-5 catalyst, the largest NOx conversion efficiency was 81.0% at low temperature, the light-off temperature （Ti） was 250（℃, the half conversion temperature （Tm） was 350℃ and the total conversion temperature （Tf） was 475℃. The La0.4 Ce0.6 Cu0.2 Mn0.8 O3/HZSM-5catalyst has the best low-temperature catalytic activity on removing soot and NOx of diesel engine.