用于NH3-SCR的有序介孔复合氧化物催化剂的设计与合成研究

Nitrogen oxides (NOx) is the key precursory pollutants for the formation of acid rain, photochemical smog, and haze. Hence, catalytic purification of NOx emission from diesel engine exhausts is an urgent target of air pollution control in China. Commercially used catalysts in NH3-SCR are V-based catalyst and Cu-zeolite catalyst, which still suffer from some drawbacks such as low stability and high cost. Therefore, the development of environmentally benign, efficient and stable vanadium-free (Ce, Fe, and Mn) NH3-SCR catalysts has become a research hotspot in the field of environmental catalysis. Ordered mesoporous materials have the advantages of large specific surface area and ordered mesoporous structure, thus exhibiting unique advantages in the field of catalysis. This project plans to assemble the redox sites and acidic sites required for NH3-SCR reaction into an ordered mesoporous structure, and carefully regulate the tight coupling of different functional sites, so that large number of active sites are fully exposed. Consequently, ordered mesoporous composite oxide catalysts with high catalytic performance was prepared. Through the comprehensive and detailed structural characterization and in situ reaction mechanism research, the structure-activity relationship and reaction mechanism of the ordered mesoporous catalysts are proposed, which provides theoretical guidance for the design and synthesis of high performance NH3-SCR catalyst.

氮氧化物（NOx）是引发酸雨、光化学烟雾和灰霾等环境污染问题的重要前体污染物。控制以柴油车为代表的机动车尾气NOx排放是我国大气污染治理的迫切需求。目前商用的氨选择性催化还原技术（NH3-SCR）使用钒基催化剂和铜基分子筛催化剂，其仍存在稳定性差和成本高昂等问题。因此，开发环境友好、高效稳定的非钒基氧化物型（Ce、Fe和Mn等）NH3-SCR催化剂是环境催化领域的研究热点。有序介孔材料具备比表面积大和孔道连续可调等优点，在催化领域表现出独特优势。本研究拟将NH3-SCR反应所需的氧化还原组分和酸性组分组装到有序介孔材料中，并调节不同功能组分的紧密耦合，使大量活性位点充分暴露，从而制备出高性能的有序介孔复合氧化物催化剂。通过全面细致的结构表征和原位反应机理研究，认识有序介孔催化剂的构效关系和反应机理，为高性能NH3-SCR催化剂的设计与合成提供理论指导。

本课题基本按计划执行。项目共发表5篇SCI学术论文，参加国内学术会议3人次，培养研究生1名。.有序介孔材料具备比表面积大和孔道连续可调等优点，在催化领域表现出独特优势。本研究将NH3-SCR反应所需的氧化还原组分和酸性组分组装到有序介孔材料中，并调节不同功能组分的紧密耦合，使大量活性位点充分暴露，从而制备出一系列高性能的有序介孔复合氧化物催化剂。其中，本研究开发一种有序介孔复合Mn-Ti-MA复合氧化物催化剂在NH3-SCR反应中表现优异的催化活性，NOx转化率在100-300 oC的宽温度窗口内大于90%，并展现出良好的抗水耐硫稳定性。这证明了这种将氧化还原组分和酸性组分组装到有序介孔材料开发高效催化剂策略的可行性，为高性能NH3-SCR催化剂的设计与合成提供理论指导。