镧系稀土对三元催化剂热稳定性的影响

The Effects of La-based Rare Earth to the Durability of Three-way Catalyst

探讨了镧系稀土对三元催化剂热稳定性能的影响。采用X 射线衍射(XRD)、扫描电镜(SEM)对含镧系稀土催化剂涂层表征。结果表明,镧系稀土能有效抑制三元催化剂金属晶粒烧结、聚集和长大,减少表面积损失。镧系稀土三元催化剂台架测试老化前后催化剂的性能分别为:老化前,CO,HC,NOx起燃温度分别为268℃、280℃、268℃,转化率97.6%、95.8%、97.1%;老化后,TCO,THC,TNOx为319℃、333℃、315℃,转化率95.2%、94.8%、96.8%,转化效率高,性能稳定;100h快速老化后装车工况测试排放值CO为1.35g/km,HC+NOx为0.45g/km,满足GB18352.2 2001标准限值。

Thermal durability of threeway catalyst with Labased rare earth was investigated. The washcoat of threeway catalyst with Labased rare earth was characterized by Xray diffraction (XRD) and scanning electron microscopy (SEM). It showed that lanthanum could prevent crystal granule from sintering, gathering and growing up, and decrease the loss of the catalyst surface. An engine testbench of the catalytic converter showed that the light-off temperatures and conversions of CO, HC, NOx had changed from 268℃ ,280℃, 268℃, and 97.6%,95.8%,97.1% before aging to 319℃ ,333℃ ,315℃ and 95.2%,94.8%,96.8% after aging, respectively, which illustrated the high efficiency and stability. A car with the catalytic converter can meet the emission limits of GB18352.22001.