【作者】 谢春英；

【导师】 龚茂初；

【作者基本信息】 四川大学 ， 物理化学， 2002， 硕士

【摘要】 采用催化净化技术来治理汽车排放污染正越来越受到人们的广泛关注，而其中储氧材料性能的优劣直接关系到汽车尾气净化催化剂的净化效果。本文详细研究了元素E和M的添加，聚合物的添加以及制备方法对CeO₂-ZrO₂固溶体的影响。通过氧脉冲吸附，XRD，H₂-TPR，BET等研究手段来表征样品的储氧能力，物相组成，可还原性能以及比表面积等各方面的性能。 实验结果表明，在CeO₂-ZrO₂固溶体中引入E后，并不能提高样品的储氧能力和可还原性能。在CeO₂-ZrO₂固溶体中引入M后，由于M-O本身具有氧吸附性能，使得样品表现出很好的储氧能力，但经过高温老化后，原四方晶相的CeO₂-ZrO₂固溶体发生了相分离，且生成了大量的M₂O₃和MO₂相，使得样品的储氧量急剧减少，可还原性能明显降低。研究表明适量聚合物的添加可以明显提高储氧材料的储氧性能和抗高温老化性能，使样品在老化前后的比表面积得到更好的保持。比较发现，以聚合物B的添加量为20％（wt）时，所得储氧材料的综合性能最佳。 由不同制备方法所得的储氧材料性能各异。研究表明，采用溶胶—凝胶法制备的样品在老化前具有最大的储氧量和比表面积，但经高温老化后，其储氧量急剧下降，表现出很差的抗高温老化性能；采用沉淀法制备的样品在老化前后，其储氧量和比表面积降幅最小，有良好的高温热稳定性能；采用浸渍法制备的样品不管老化与否，其储氧量并不随着储氧温度的改变而大起大落，表现出较好的热稳定性。更多还原

【Abstract】 Using catalysts to purify automotive exhaust gas has more and more been regarded by human society. It is generally accepted that the most important factor in the catalyst is the oxygen storage materials, which have a direct relation to the puring performance. In present paper, the influence of additives and preparation methods on the performance of oxygen storage materials was studied in detail. Oxygen pulse technique, XRD, H2-TPR, and BET surface area analysis methods were used to characterize the oxygen storage capacity (OSC), textual property, reduction behavior and surface area of the materials above respectively.The results indicate that the OSC and reductibility of the CeO2-ZrO2 solid solution are not improved after adding E ions. While after incorporating M ions into the CeO2-ZrO2, the samples exhibit high OSC probably by reason that M-O itself also has good capability of oxygen adsorption. After aged at high temperature, the OSC of these samples decreased dramatically for the formation of M2O3 and MO2 and for the separation of tetragonal phase of CeO2-ZrO2.The appropriate addition of polymers into oxygen storage materials can improve the OSC obviously and can make the samples become high-temperature-resistant materials with favorable surface area even after aged at high temperature. When 20%(wt) PolymerB was added, the oxygen storage materials get the most ideal synthesis properties.The materials prepared by various methods show different properties. The studies imply that the samples prepared by sol-gel method have the highest OSC and special surface area, but after calcinated at 1000? for 2h, the OSC and special surface area decreased sharply, meaning a bad thermal stability. The OSC and special surface area of the samples prepared by precipitation keep very well after aged, exhibiting a promising thermal resistance. While the samples prepared by dipping method have a much more stable OSC at different temperature, that is, they have a good thermal stability.更多还原