Study on the properties of |Pt/ Ba/TiCeO catalyst for NOx storage and resistance to SO2
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摘要: 采用共沉淀-浸渍法制备了新型NOx储存-还原催化剂Pt/Ba/TiCeO，考察了不同反应气氛对载体和催化剂上NOx存储性能的影响，并用Ｘ射线衍射（XRD）和程序升温脱附（TPD）等方法对催化剂进行了表征。结果表明，Pt/Ba/TiCeO中TiCeO和BaO/TiCe具有较大比表面积（230m2/g和90m2/g），Ba不仅起结构助剂作用，使催化剂的结构稳定，而且Ba的碱性又有利于NOx的吸附。Pt主要起催化氧化作用，催化NO氧化生成NO2，NO2 比NO 更容易与BaO/TiCeO成盐，促进NOx的存储。Pt/Ba/TiCeO催化剂中存在一储存活性位，它们是Ba位与TiCeO位组合。SO2对Pt/BaO/TiCeO催化剂的NOx储存性能影响较小，主要是Pt/BaO/TiCeO上形成的硫酸盐分解还原峰温度较低（410℃），硫化物易分解还原脱除，其抗硫中毒能力较强。
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关键词:
- NOx /
- 存储 /
- Pt/BaO/TiCeO /
- 贫燃 /
- 抗硫
Abstract: A novel NOx-storage-reduction (NSR) catalyst of Pt/Ba/TiCeO was prepared by coprecipitation-impregnation method and the effects of the reaction atmosphere on its properties for NOx storage was investigated. The catalysts were characterized by means of N2 adsorption, X-ray diffraction (XRD) and temperature-programmed desorption(TPD). The results indicate that the specific surface areas of TiCeO and BaO/TiCeO were as high as 230m2/g and 90m2/g respectively. For the component of Ba, not only did it act as structural promoter for enhancing the structure stability of the catalysts Pt/Ba/TiCeO, but also it increased NOx storage capacity due to its basicity. Pt catalyzed oxidization of NO to NO2, and it is easier for NO2 to react with BaO/TiCeO to form nitrate than NO. TiCeO in Pt/Ba/TiCeO catalyst exhibited as both support and storage component in the NOx storage-reduction process. There were some active sites composed of Ba and TiCeO in the catalyst of Pt/Ba/TiCeO. The presence of SO2 has less effect on NOx storage capacity of Pt/Ba/TiCeO catalyst because the formed sulfate on the surface of the catalyst was unstable and was easily removed by reduction.-
Key words:
- NOx /
- storage /
- Pt/Ba/TiCeO /
- lean-burn /
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sulfur-resistance
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