【摘要】 Pt/TiO₂-Al₂O₃对CO,HC以及NOx均有较好的催化氧化活性,但钛铝载体在高温下易发生相变,导致Pt团聚烧结而失活,CeO₂作为助剂可与贵金属发生电子间作用,提高其抗老化性能。通过分步负载的方法,采用浸渍法先对钛铝载体负载不同质量分数的CeO₂,烘干后再对其二次浸渍,负载0.7%（质量分数）的Pt,考查CeO₂负载量对催化剂催化氧化活性的影响,由此筛选出性能较好的催化剂,在1000℃条件下进行老化处理,对比老化前后其物理化学性质以及催化性能,最后对催化剂老化样进行了物相分析。结果表明负载1%（质量分数）的CeO₂不但可以提高催化剂对CO和C₃H₆的氧化活性,而且显著改善了催化剂的抗老化性能,老化样的NO₂最大生成量可达112×10^-6,较未添加CeO₂的催化剂老化样增加了23×10^-6,且其温度窗口更宽,说明CeO₂作为Pt/TiO₂-Al₂O₃催化剂助剂有很大的潜在应用价值。更多还原

【Abstract】 Pt/TiO₂-Al₂O₃ catalyst had better activity than others for CO,HC and NOxoxidation,but at high temperature,TiO₂-Al₂O₃ carrier was prone to phase transition,which easily led to the inactivation caused by Pt aggregation and sintering. As an additive,CeO₂ could improve the aging resistance performance of the catalyst by electronic effect with precious metals. Using the stepwise impregnation method,different mass fractions of CeO₂ were supported on the surface of TiO₂-Al₂O₃ carrier firstly; after drying,0. 7%（ mass fraction） Pt was also supported with the method of impregnation on each sample. The effect of CeO₂ loading amount on the catalytic oxidation activity was investigated,then the catalysts with excellent performance were selected and aged at 1000 ℃. After aging,the physical and chemical properties as well as the catalytic performance of the aged samples were compared with the fresh samples.Last,the phase analysis of the aged samples was carried out. The results showed that supporting 1%（ mass fraction） CeO₂ could not only improve the oxidation activity for CO and C₃H₆,but also significantly improve the anti-aging performance of the catalyst; the maximum generation of NO₂ reached 112 × 10- 6under the aged sample,which increased by 23 × 10^-6 compared to the aged catalyst without CeO₂,and the temperature window was wilder. The result indicated that CeO₂ possessed a great potential as an additive in Pt / TiO₂-Al₂O₃ catalyst.更多还原