MnOx-CeO2 mixed oxide catalysts for complete oxidation of formaldehyde:: Effect of preparation method and calcination temperature
MnOx-CeO2 mixed oxide catalysts for complete oxidation of formaldehyde:: Effect of preparation method and calcination temperature
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DOI：
10.1016/j.apcatb.2005.08.004
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发表时间：
2006-02-22
影响因子：
22.1
通讯作者：
Shen, WJ
中科院分区：
文献类型：
--
作者：
Tang, XF;Li, YG;Shen, WJ
采用溶胶-凝胶法、共沉淀法和改进的共沉淀法制备了MnOx-CeO 2复合氧化物，研究了其对甲醛的完全氧化性能。通过H-2-TPR和XPS对催化剂进行结构分析，发现改性共沉淀法制备的催化剂比溶胶-凝胶法和共沉淀法制备的催化剂表面存在更多的Mn ~（4+）物种和更丰富的晶格氧，对甲醛完全氧化具有更高的催化活性。进一步考察了焙烧温度对改性共沉淀法制备的MnOx-CeO 2复合氧化物的结构特征和催化性能的影响，在773 K焙烧的催化剂在373 K的温度下甲醛转化率达到100%.在773 K以下煅烧的样品，由于形成了MnOx-CeO 2固溶体，XRD测量没有检测到任何与锰氧化物相对应的衍射峰。而在773 K以上煅烧的样品中，观察到了与MnO 2相对应的衍射峰，表明MnO 2和CeO 2发生了相分离。因此，据推测，MnOx和CeO 2之间的强相互作用，这取决于制备路线和煅烧温度，在确定对甲醛的完全氧化的催化活性中起着至关重要的作用。(c)2005 Elsevier B. V.保留所有权利。
MnOx-CeO2 mixed oxides prepared by sol-gel method, coprecipitation method and modified coprecipitation method were investigated for the complete oxidation of formaldehyde. Structure analysis by H-2-TPR and XPS revealed that there were more Mn4+ species and richer lattice oxygen on the surface of the catalyst prepared by the modified coprecipitation method than those of the catalysts prepared by sol-gel and coprecipitation methods, resulting in much higher catalytic activity toward complete oxidation of formaldehyde. The effect of calcination temperature on the structural features and catalytic behavior of the MnOx-CeO2 mixed oxides prepared by the modified coprecipitation was further examined, and the catalyst calcined at 773 K showed 100% formaldehyde conversion at a temperature as low as 373 K. For the samples calcined below 773 K, no any diffraction peak corresponding to manganese oxides could be detected by XRD measurement due to the formation of MnOx-CeO2 solid solution. While the diffraction peaks corresponding to MnO2 phase in the samples calcined above 773 K were clearly observed, indicating the occurrence of phase segregation between MnO2 and CeO2. Accordingly, it was supposed that the strong interaction between MnOx and CeO2, which depends on the preparation route and the calcination temperature, played a crucial role in determining the catalytic activity toward the complete oxidation of formaldehyde. (c) 2005 Elsevier B.V. All rights reserved.