采用恒定pH共沉淀法制备了Co2.5 Mg0.5 Al0.92 Ce0.08水滑石前驱体,经过700℃焙烧后,得到CM ACe8催化剂并负载不同含量的K.利用现代表征技术对其进行结构表征,并进行碳烟燃烧和碳烟与NOx同时消除活性测试.XRD和EXAFS测试表明,催化剂中的主要物相是Co3O4.从BET结果看出,利用水滑石前驱体得到的催化剂比表面积较大,更加利于反应物种在催化剂上吸附.H2-TPR表征说明,K的负载促进了催化剂样品中活性氧物种的释放,使得催化剂碳烟燃烧活性和NOx储存活性都得到了提高.但对于同时消除反应,由于NOx储存量过大,碳烟含量恒定,使得NOx消除活性降低,证明高含量的K对该反应起到了抑制作用,其中K的最佳负载量为2%.%Co2.5Mg0.5Al0.92Ce0.08 hydrotalcite-like compounds (HTlc) were prepared by a con-stant-pH co-precipitation .After calcination ,CMACe8 catalyst was obtained as well as K-im-pregnated ones .Their structure and physico-chemical properties were examined by charac-teristic techniques .The samples were applied to soot combustion ,lean-burn NOx storage and simultaneous NOx-soot removal .The results of XRD and EXAFS suggest that the main Co-containing phase in the catalyst is Co3 O4 .According to BET data ,the specific surface area of catalysts ,which were derived from hydrotalcite-like compounds ,is large enough to absorb more reactant gas .The results of H2-TPR indicate the addition of K promote the amount of active oxygen ,leading to the high soot oxidation activity and large NOx storage capacity . However ,too much stored NOx and constant amount of soot result in low NOx reduction percentage .This demonstrates that high K-impregnation amount restrain the simultaneous NOx-soot removal reaction .The optimal value is 2% .
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