被动式氨SCR系统是一种应用在稀燃发动机，可减少NO_x排放，生产SCR用氨的后处理方法，该系统使用NO与H₂作为原料气在催化剂的作用下产生氨气用于后续SCR脱硝。通过试验研究，采用自蔓延燃烧合成（SHS）法合成了Pd_0.01Cu_xCe_(1-x)/2Zr_(1-x)/2O_y(x=0,0.1,0.2,0.4)催化剂。用XRD、BET、Raman、H₂-TPR、XPS、原位表征等方法研究了它们的催化活性。建立了Pd_0.01Cu_xCe_(1-x)/2Zr_(1-x)/2O_y(x=0,0.1,0.2,0.4)催化剂的反应性与物种组成、酸性质和氧化还原性能的关系。结果表明，适量的铜掺杂可以形成更多的酸性位点，调节表面元素的价态分布，有助于产生更高的催化效率。其中，Pd_0.01Cu_0.1Ce_0.45Zr_0.45O_x的氨转化率最高，反应温度窗口较宽（225~375 ℃），NO向NH₃转化率大于90%。这是由于高度分散的CuO增强了CuO与Ce_0.5Zr_0.5O₂载体之间的相互作用，从而提高了催化活性。

The passive ammonia SCR system is a novel aftertreatment method for lean-burn engine to reduce NO_x emission and produce necessary ammonia for SCR. The reaction between NO and H₂ was activated and ammonia gas of SCR, denitration was then prepared under the action of a catalyst. Pd_0.01Cu_xCe_(1-x)/2Zr_(1-x)/2O_y catalysts with x parameter of 0, 0.1, 0.2 and 0.4 were synthesized through self-propagating combustion reaction method. The activities of catalysts were investigated according to XRD, BET, Raman, H₂-TPR, XPS, in situ DRIFTS. The relationship between the catalyst reactivity and species composition, acid property, and redox behavior was established in the end. The results showed that a moderate amount of Cu doping could significantly form more acid sites and tune the valence distribution of surface elements so as to lead to a high catalytic efficiency. Pd_0.01Cu_0.1Ce_0.45Zr_0.45O_x had the highest ammonia conversion rate among all the catalysts with a wide reaction temperature window of 225-375 ℃. The conversion rate of NO to NH₃ was beyond 90% with the catalyst due to the improved catalytic activity led by the fact that highly-dispersed CuO enhanced the interaction between CuO and Ce_0.5Zr_0.5O₂ carrier.