王攀，孙川,张博,罗鹏,雷利利.MnOx-CeO2复合氧化物催化氧化柴油机NO性能研究[J].内燃机工程,2018,39(2):53-58.
MnOx-CeO2复合氧化物催化氧化柴油机NO性能研究
Research on catalytic oxidation of NO from diesel engine using MnOx-CeO2，composite oxides
DOI：
关键词:柴油机  溶胶凝胶法  MnOx-CeO2复合氧化物  NO氧化  氧空位
Key Words:diesel engine  solgel method  MnOx-CeO2 composite oxides  NO oxidation  oxygen vacancy
基金项目:国家自然科学基金项目（51676090）；江苏省自然科学基金项目（BK20150513）；江苏大学高级人才项目（14JDG152）
作者单位
王攀，孙川,张博,罗鹏,雷利利 江苏大学 汽车与交通工程学院，镇江 212013 
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摘要:为了研究MnOx-CeO2复合氧化物催化氧化柴油机NO的性能，采用溶胶凝胶法制备了不同Mn/Ce摩尔比的xMn10Ce/γ-Al2O3（x=5，6，7，8）催化剂。利用X射线衍射（X-ray diffraction，XRD）、X射线光电子能谱（X ray photoelectron spectroscopy，XPS）和H2 程序升温还原（H2temperature programmed reduction，H2-TPR）技术分别对其物相结构、元素价态及还原性能进行了表征。结果表明：CeO2晶粒尺寸随Mn含量增加而逐渐变大，同时添加适量的Mn也有利于提高催化剂中Mn4+的数量，从而促进NO氧化；当x=6时，催化剂的氧化还原性能最好。最后，基于模拟气试验平台考察了不同Mn/Ce比对xMn10Ce/γ-Al2O3催化剂氧化NO性能的影响。结果表明：在350℃时，NO浓度达饱和所需时间和反应速率与Mn添加量呈非线性关系；在250~450℃范围内，6Mn10Ce/γ-Al2O3的NO氧化性能最好，其NO浓度在350℃时最先达到稳定，仅需4 min，但在450 ℃时则延长至6 min，这主要是受热力学平衡及随反应进行活性氧数量及氧空位逐渐饱和共同作用的结果。
Abstract:In order to research into the influence of MnOx-CeO2 composite oxides on catalytic oxidation of NO from diesel engine, a series of xMn10Ce/γ-Al2O3（x=5, 6, 7, 8) catalysts with different Mn/Ce mole ratio were prepared by the solgel method. A combination of characterization techniques, namely X-ray diffraction(XRD), X-ray Photoelectron Spectroscopy（XPS) and H2 Temperature Programmed Reduction（H2-TPR), was adopted to analysis its phase structure, element valence and reducibility, respectively. Results illustrate that the grain size of ceria gradually increases with the rise in Mn content, and the addition of appropriate amount of Mn is also beneficial to the increase of the number of Mn4+ in the catalyst, so as to promote the oxidation of NO. When x is equal to 6, the catalyst has the best redox properties. Finally, the impact of different Mn/Ce mole ratio on NO oxidation performance of xMn10Ce/γ-Al2O3 catalysts was investigated based on a simulated gas bench test. Test results show that at a temperature of 350 ℃, the time required for NO concentration to reach saturation and the reaction rate are nonlinear with the amount of Mn added when the temperature is between 250 ℃ and 450 ℃, the NO oxidation properties of 6Mn10Ce/γ-Al2O3 are the best. At this time, the timing required for NO concentration to reach stability is only 4 min, but it is extended to 6 min at 450 ℃, which is mainly the result of a combination of the thermodynamic equilibrium as well as the amount of active oxygen and the gradual saturation of oxygen vacancy during the reaction.
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