类水滑石衍生高效NOx存储还原催化剂的构建及催化机制研究

The NOx emission control from lean-burn vehicle exhausts is key to the protection of our atmosphere, which can effectively prevent the air pollution becomes worse. Recently, NOx storage and reduction (NSR) catalysts have received increasing attention because its operation principle is very suitable for mobile pollution sources. In this proposed project, we would like to develop novel NSR catalysts from layered double hydroxides (LDHs) by tuning the chemical composition, controlling the morphology and particle size,intercalation of organic anions, LDH exfoliation/delamination, or synthesis of hybrid inorganic nanocomposites, etc. In the meantime, we would like to systematically study the influences of catanic metal composition, noble metals doping, and types of reducing reagents,investigate the NOx adsorption sites and reduction mechanism, and evaluate the possiblity of using these novel NSR catalysts in the real vehicle exhaust treatment conditions. The ultimate goal of this proposed project is to deveolop novel NSR catalysts which are economical, highly efficient, highly stable, and with our own and independent intellectual property right.We wish this project could make great contribution to the vehicle exhaust NOx treatment and lead to a sustainable development of our society.

贫油燃烧机动车尾气中氮氧化物（NOx）排放的控制和去除是防止大气污染日趋恶化的重要手段之一。NOx存储还原（NSR）催化剂由于其操作原理非常适用于贫油燃烧机动车移动污染源而得到广泛关注。本课题拟通过对类水滑石的化学组成的调变、颗粒形貌和大小的控制、有机阴离子插层、纳米单层的剥离、无机-无机材料杂化等手段，构建出存储性能更高、抗硫性更优、长期稳定性更好的新型NSR催化剂。同时，系统研究不同金属阳离子组成、贵金属负载和不同还原性气氛对NOx选择性还原的影响；深入探究NOx在催化剂表面的吸附位和吸-还原过程及催化机理；评估构建出的NSR催化剂在汽车尾气处理装置的实际工况条件下应用的可行性。本项目的最终目标是构建具有我国自主知识产权的、经济高效的NSR催化剂，减少贫油燃烧机动车尾气中NOx的排放，为改善我国大气污染现状和实现我国社会经济可持续发展提供技术支撑。

贫油燃烧机动车尾气中氮氧化物（NOx）排放的控制和去除是防止大气污染日趋恶化的重要手段之一。NOx存储再还原（NSR）催化剂由于其操作原理非常适用于贫油燃烧机动车移动污染源而得到广泛关注，其中，以类水滑石衍生混合金属氧化物为前驱体制备NSR催化剂已取得一些研究进展，但其NOx存储性能仍有待提升。因此，本课题通过探究不同因素（温度、老化时间、pH等）对类水滑石合成的影响，控制其颗粒形貌和大小；通过有机阴离子插层、纳米单层的剥离与氧化石墨烯杂化等手段，构建存储性能更优的NSR催化剂。对合成的催化剂进行XRD, SEM ,TEM等表征，确定其形貌结构。同时，探究不同金属阳离子组成、贵金属和碱金属碳酸盐负载和不同还原性气氛对NOx选择性还原的影响，并初步探究NOx在催化剂表面的吸附位和吸-还原过程及催化机理，最终构建出循环稳定使用达8次、存储NOx量高达78.4%、抗H2O性能和热稳定性良好的NSR催化剂，为改善我国大气污染现状和实现我国社会经济可持续发展提供技术支撑。