过渡金属掺杂二氧化铈多孔纳米催化剂的制备及其净化汽车尾气的研究

Automobile exhaust purification is of important practical significance to reduce PM2.5 and “haze” weather. However, most commonly used three-way catalysts for automobile exhaust purification containing a large number of noble metals are limited to further develop by some drawbacks, such as the expensive price, easily poisoned, easily sintering at high temperatures.. This project intends to use metal-organic frameworks nanomaterials as precursor to prepare the transition metal-doped ceria porous nanomaterials, achieving the development of non-noble metal, cheap, highly efficient and stable catalysts. By adjusting the morphology, the type and structure of the organic ligands in the precursor, the final materials will possess controllable morphology and continuously tunable specific surface area. Additionally, this method can dope a variety of transition metal ions homogenously. The highly dispersed transition metal ions not only can promote the oxygen storage capacity of CeO2, but also can enhance the synergetic effect between transition metal ions and CeO2, resulting in improving the catalytic activity. This project makes use of the features of highly dispersed doping transition metal ion and controllable specific surface area to cooperatively enhance the catalytic activity, and reveals the regularities of relevancy between doped ions, structure and properties, and the multi-component synergistic mechanism, to achieve effective elimination of CO and NOx in automobile exhaust. The research has important academic significance and application value for opening up a new road towards the controllable preparation of transition metal doped ceria porous nanomaterials, developing novel materials in automobile exhaust purification, environmental protection, and rare earth resources utilization with high quality and high efficiency.

汽车尾气净化对减少PM2.5和雾霾天气有重要意义，而目前尾气净化常用的三元催化剂中使用大量贵金属，其价格昂贵、易中毒、高温下易烧结团聚等不足限制了其发展。本项目拟以金属有机框架纳米材料为前驱体制备过渡金属掺杂CeO2多孔纳米材料，实现开发非贵金属、廉价、高效、稳定的催化剂的目标。通过调控前驱体形貌和有机配体种类与结构实现最终材料形貌可控、比表面积连续可调，该方法还具有掺杂多种过渡金属离子且高度分散的优势。高度分散的过渡金属离子既可提高CeO2储放氧能力，又可增强其与CeO2间的协同作用，进而提升催化活性。本项目利用过渡金属离子掺杂和比表面积调控协同地增强催化剂的催化活性，揭示掺杂离子、结构与性能相关性的规律和多组份协同作用机制，实现有效处理汽车尾气中CO及NOx。该研究对丰富此类材料制备方法，新型尾气净化材料开发、环境保护和稀土资源高质高效利用都具有重要的学术意义和应用价值。

在项目执行的三年期间，围绕氧化铈纳米材料的结构调控和一氧化碳催化氧化性质提升开展相关研究。通过有机配体及MOFs前驱体的选择和形貌调控，获得形貌和比表面积不同的氧化铈纳米材料。构建过渡金属/氧化铈复合纳米材料，研究了表面元素价态、表面氧空穴等关键微结构参数对催化性质的影响，筛选出三壳中空CuO/CeO2-8%纳米球催化剂具有很好的催化活性和循环稳定性。构建了不同形貌的Au/CeO2复合纳米材料，考察了形貌等结构因素对催化性质的影响。进一步拓展了基于MOFs前驱体制备中空结构过渡金属氧化物纳米材料的方法，并延伸了其污染性气体检测性质的研究。