The highly active catalysts of nanometric CeO2-supported cobalt oxides for soot combustion
The highly active catalysts of nanometric CeO2-supported cobalt oxides for soot combustion
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纳米CeO2负载氧化钴高活性烟灰燃烧催化剂
DOI：
10.1016/j.apcatb.2008.03.017
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发表时间：
2008-10-25
影响因子：
22.1
通讯作者：
Yang, Qing
中科院分区：
文献类型：
--
作者：
Liu, Jian;Zhao, Zhen;Yang, Qing
采用超声辅助浸渍法制备了不同Co/Ce原子比的纳米CeO2负载钴氧化物材料。研究了一系列CoOx/nmCeO(2)催化剂的碳烟燃烧性能，并进行了X射线衍射、X-射线光电子能谱、拉曼光谱、紫外-可见光谱和FNR光谱表征。结果表明，在Co负载量较低的样品中形成了CoO或Co-Ce固溶体，而在高Co负载量的样品中形成了Co3O4。与纳米CeO2相比，CoOx/nmCeO(2)催化剂能进一步促进碳烟燃烧。这与纳米CeO2负载CoO_2后催化剂氧化还原性能的提高有关。氢气气氛下的TPR实验结果表明，Co的存在使催化剂的还原温度从555℃(纳米CeO2)降至286℃(Co-20/nmCeO(2))。另一方面，由于纳米粒子效应和NO2的生成，本研究制备的Co-m/nmCeO(2)氧化物催化剂具有很高的碳烟燃烧活性。在Co-20/nmCeO(2)催化剂上，T-10为286℃，T-50为368℃，T-90为418℃，S-CO_2(M)为98.8%。与空白情况(即无催化剂)相比，燃烧温度T-50降低了200℃以上，S二氧化碳(M)增加了40%。而CO2对碳烟颗粒燃烧的催化活性与负载型铂催化剂相当，是目前报道的松散接触条件下碳烟燃烧最好的催化剂体系。这样的碳烟燃烧温度可以保证在柴油机排放的条件下，滤清器上的催化剂立即被激活。(C)2008爱思唯尔B.V.保留所有权利。
Nanometric CeO2-supported cobalt oxide materials with variable Co/Ce atomic ratios were prepared by the method of ultrasonic-assisted incipient-wetness impregnation. The catalytic behaviors of a series of CoOx/nmCeO(2) catalysts have been studied for soot combustion, XRD, XPS, Raman, UV-vis DRS and FNR spectroscopy characterization results indicated that CoO or cobalt-cerium solid solutions were formed in the samples with the low Co loading amount, while Co3O4 was formed in the samples with high Co loading amount. CoOx/nmCeO(2) catalysts can further promote soot combustion in contrast to nanometric CeO2. This improvement is related to the increase in the redox properties of the catalysts brought about by loading cobalt oxide on nanometric CeO2. The TPR experiment results under hydrogen atmosphere indicated that the presence of Co decreases the reduction temperature of catalyst from 555 degrees C (nanometric CeO2) to 286 degrees C (Co-20/nmCeO(2)). On the other hand, attributing to nanoparticle effect and NO2 formation, Co-m/nmCeO(2) oxide catalysts prepared in this study have very high activity for soot combustion. The best catalytic activity was obtained over Co-20/nmCeO(2) catalyst that T-10, T-50, T-90 were 286 degrees C, 368 degrees C. 418 degrees C, respectively, and S-CO2(m) was 98.8%. Compared with the blank case (i.e., without catalyst) for soot combustion, T-50 decreased by more than 200 degrees C and S-CO2(m) increased by 40% point. And CO2 this catalytic activity for the combustion of soot particle is as good as supported Pt catalysts, which is the best catalyst system so far reported for soot combustion under loose contact conditions. This temperature of soot combustion can ensure immediate activation of the catalyst on the filter under the conditions of diesel engine emissions. (c) 2008 Elsevier B.V. All rights reserved.