贫燃条件下汽车尾气中氮氧化物的催化净化

以碳氢化合物为还原剂选择性还原汽车尾气中的NOx是研究较早且较多的一种方法。以NH3或尿素为还原剂催化还原NOx,NOx储存还原型三效催化剂以及NOx直接催化分解等净化方法也得到了广泛的研究。低温等离子体,以水滑石类化合物为前体的催化剂以及利用改性碳纤维作还原剂等是近几年新发展的净化方法。在这些方法中,钙钛矿型复合氧化物和NOx储存还原型三效催化剂是目前该领域的研究热点。指出今后应进行深入的机理研究,为催化剂的设计提供理论指导。

Research progress in NOx catalytic purification in automobile exhaust under lean-burn condition

The research progress in the catalytic purification for NO_ x in the automobile exhaust under the lean-burn condition was reviewed,and its development direction was also presented.The selective catalytic reduction of NO_ x used hydrocarbons as reductant was developed long ago and has now become the focus of attention.The selective catalytic reduction of NO_ x used ammonia or urea as reductant,the NO_ x storage-reduction triple effect catalyst and the direct decomposition of NO_ x are also being studied.Areas such as non-thermal plasma,mixed oxides derived from hydrotalcite-like compound and catalytic NO_ x reduction used modified carbon fiber as reductant,etc.have been developed in recent years.Of many fields,the perovskite-type-oxide and the NO_ x storage-reduction triple effect catalyst are the focus of the research.The mechanism of all these reactions should be probed into the deep,and give a good theoretical direction for the design of catalysts.