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制备了低Pt、Rh担载量的稀土基催化剂体系 ,研究了贵金属担载量、催化剂高温老化、抗硫水热老化和SO2 对催化活性的影响。结果表明 :随着贵金属质量分数从 0 2 5 %降低到0 1% ,CO、碳氢化合物 (HC)和NO的起燃温度分别平均提高 2 0℃ ;随着m(Pt)∶m(Rh)从 5∶1提高到 9∶1,CO、HC和NO的起燃温度分别提高 17、2 0和 5 3℃ ;当在反应体系中添加SO2 ,随SO2 体积分数从 0 0 0 2 %增加到 0 0 1% ,CO和NO的起燃温度和完全转化温度分别平均提高2 0℃ ,而对于HC ,催化活性几乎保持不变 ;催化剂在水热含硫条件下连续老化 4 0 0h ,CO、NO和HC的起燃温度分别为 2 5 2、2 6 7和 30 3℃ ,仍具有良好的反应活性。表明该稀土基催化剂在一定条件下 ,能满足汽车实际工况的要求
The rare earth-based catalyst system with low Pt loading and Rh loading was prepared. The effect of noble metal loading, high temperature aging of catalyst, thermal aging resistance to sulfur water and SO2 on catalytic activity were studied. The results showed that the light-off temperature of CO, HC and NO increased by 20 ℃ on average with the decrease of precious metal content from 0 2 5% to 0 1%. With the increase of m (Pt): m (Rh ) Increased from 5: 1 to 9: 1, the ignition temperatures of CO, HC and NO increased by 17.2 and 53 ℃, respectively. When SO2 was added to the reaction system, the ignition temperature increased with the SO2 concentration from 0% 0 2% To 0 0 1%, the light-off temperature and complete conversion temperature of CO and NO increased by 20 ℃ on average, while the catalytic activity almost remained unchanged for HC. The catalyst was continuously aged 400h under CO 2 and CO , NO and HC light-off temperature of 25,26,77 and 30 3 ℃, still has good reactivity. Show that the rare earth-based catalyst under certain conditions, to meet the actual requirements of the car