【摘要】 研究了以宜兴堇青石蜂窝体为载体，γ－Ａｌ_２Ｏ_３为洗涂层的Ｌａ和Ｃｅ的催化活性与Ｌａ、Ｃｅ物质量的比例关系；探讨了 Ｌａ、 Ｃｅ配比对 Ｐｄ－ＴＷＣ性能的影响．结果表明， Ｐｄ－ＴＷＣ对汽车尾气中 ＣＯ、 ＨＣ、 ＮＯ的催化活性随 Ｌａ、Ｃｅ比的不同而变化，当 ｎ（Ｌａ）∶ ｎ（Ｃｅ）＝ １∶ ４时，催化活性最好，此时，其表面过剩氧量最多； ＸＰＳ分析表明 Ｃｅ以十 ３、＋ ４价共存，且Ｃｅ^４＋所占比例在所有样品中最大，为６０％． Ｌａ、Ｃｅ虽为性质相近的稀土元素，但它们在提高Ｐｄ－ＴＷＣ的活性上存在明显的协同效应更多还原

【Abstract】 The relationship between the activity of La-Ce Catalysts and molar ratio of La-Ce was studied in the paper. These catalysts were prepared by impregnation method using cordierite holeycomb monoliths obtained from Yixing coated by γ-Al₂O₃ as carrier. The effect of the molar ratio of La-Ce on the property of Pd-TWC was also studied. consults showed that the catalytic astivity of Pd-TWC in Purifying CO, HC and NO varied with the ratio of La-Ce. The best catalytic activity was obtained when the ratio was l: 4. Under this circumstances, the amount of resodual oxygen on its surface was largest. XPS results showed that Ce⁴⁺ coexited with Ce³⁺ and the relative amount of Ce⁴⁺ is the biggest in all the samples and equaled 60%. La and Ce had a synergestic action on improving catalytic astivity of Pd-TWC.更多还原