稀土钙钛矿型稀燃氮氧化物阱催化剂的理性设计与机理研究

项目名称： 稀土钙钛矿型稀燃氮氧化物阱催化剂的理性设计与机理研究

项目编号： No.U1232118

项目类型： 联合基金项目

立项/批准年度： 2013

项目学科： 物理学II

项目作者： 李新刚

作者单位： 天津大学

项目金额： 70万元

中文摘要： 稀燃氮氧化物阱（LNT）技术是解决稀燃发动机尾气中氮氧化物（NOx）污染问题的有效途径之一。常用的商业LNT催化剂中含有贵金属铂，价格昂贵，易高温烧结和硫中毒。我国稀土资源丰富，本项目拟以价格便宜、具有高"NOx储存–还原"催化活性和抗硫能力的稀土钙钛矿型催化剂替代常用的铂基LNT催化剂：通过调变钙钛矿A位和B位元素组成，拓宽工作温度窗口，同时提高NOx催化消除活性和抗硫能力。利用同步辐射原位X射线吸收光谱技术，获得催化剂A位和B位组成元素在NOx氧化、储存和还原过程中元素价态和周围原子尺度局域配位结构的变化。结合原位红外光谱等表征手段，找出催化剂的NOx氧化、储存和还原活性中心以及NOx的储存形式和位置；弄清催化剂各组成元素间的催化协同作用机制，提出反应机理和模型。本项目的成功实施，将为稀燃发动机尾气净化技术提供新的理论方法，促进我国汽车和环保产业的发展，具有重要的科学意义和应用前景。

中文关键词： 稀薄燃烧；氮氧化物；钙钛矿；催化消除；储存还原

英文摘要： The Lean NOx Traps (LNT) technique is regarded as one of the promising approaches to remove NOx under lean-burn conditions. The commercial LNT catalysts usually contain noble metal, e.g. Pt that is easily sintered and lost at a high operating temperature, with a poor sulfur tolerance. Our previous studies showed that the rare-earth perovskite-type catalyst doped with alkali metal element at the A site contained the NOx oxidizing, storage and reduction sites. And, it presented an excellent De-NOx catalytic performance in successively alternative lean/rich atmospheres. Because the rare-earth resources are rich in our country, in this project, we intend to use rare-earth perovskite oxides to substitute the noble metals based LNT catalysts: broaden the operating temperature window, and improve De-NOx ability and sulfur-tolerance through adjusting the composition of the A and B site elements. Moreover, the in-situ X-ray absorption spectroscopy and other characterization techniques will be employed to characterize the catalyst structure, evaluate the catalytic performance, and capture the reaction intermediate species. According to these results we intend to distinguish the NOx oxidizing, storage and reduction active sites, find out the catalytic synergetic effect between the composition elements of the perovskite, an

英文关键词： Lean-burn；Nitrogen oxides；Perovskite；Catalytic reduction；Storage-reduction