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首页> 外文期刊>Catalysis science & technology >Effect of preparation method on the solid state properties and the deN(2)O performance of CuO-CeO2 oxides
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Effect of preparation method on the solid state properties and the deN(2)O performance of CuO-CeO2 oxides

机译：制备方法对固态特性的影响和CUO-CEO2氧化物的DEN（2）O性能

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摘要

The present work aims at investigating the catalytic decomposition of N2O over CuO-CeO2 single or mixed oxides prepared by different synthesis routes, i.e., impregnation, precipitation and exotemplating. To gain insight into the particular role of CeO2 as well as of CuO-CeO2 interactions, three different types of materials were prepared and tested for N2O decomposition both in the absence and presence of excess O-2: (i) bare CeO2 prepared by precipitation and exotemplating, (ii) CuO/CeO2 oxides synthesized by the impregnation of CeO2 samples prepared in (i) with CuO, and iii) single stage CuO-CeO2 mixed oxides synthesized employing the co-precipitation and exotemplating methods. The corresponding commercial samples were also examined for comparison purposes. All materials were characterized by N-2 adsorption at -196 degrees C, X-ray diffraction (XRD), H-2 temperature-programmed reduction (H-2-TPR), X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy (micro-Raman) and scanning electron microscopy (SEM). The results demonstrated the key role of the preparation procedure on the direct catalytic decomposition of N2O. Among the bare CeO2 samples, the best performance was obtained with the samples prepared by the precipitation method, followed by exotemplating, while commercial CeO2 showed the lowest performance. All bare oxides demonstrated low N2O conversion, never exceeding 40% at 600 degrees C. Amongst the CuO-CeO2 oxides, the optimum performance was observed for those prepared by co-precipitation, which achieved complete N2O conversion at 550 degrees C. In the presence of excess oxygen in the feed stream, a slight degradation is observed, with the sequence of deN(2)O performance remaining unchanged. The superiority of the Cu-Ce mixed oxides prepared by precipitation compared to all of the other materials can be mainly ascribed to their excellent redox properties, linked to Ce4+/Ce3+ and Cu2+/Cu+ redox pairs. A redox mechanism for the N2O catalytic decomposition is proposed, involving N2O adsorption on Cu+ sites and their regeneration through Cu-ceria interactions.
机译：目前的工作旨在研究通过不同合成途径制备的CUO-CEO2单一或混合氧化物的N2O催化分解，即浸渍，沉淀和外置。为了深入了解CEO2以及CUO-CEO2相互作用的特定作用，准备了三种不同类型的材料，并在不存在和存在过量O-2的情况下对N2O分解进行了测试：（i）通过降水制备的裸露CEO2 （ii）（ii）CUO/CEO2氧化物通过（i）用CUO制备的CEO2样品浸渍和III）单阶段CUO-CEO2混合氧化物合成的CEO2氧化物合成。还检查了相应的商业样品以进行比较。所有材料的特征在-196度C，X射线衍射（XRD），H-2温度衍射还原（H-2-TPR），X射线光电子光谱（XPS），Micro-Raman中，以N-2的吸附为特征。光谱（微拉曼）和扫描电子显微镜（SEM）。结果表明，制备程序在N2O的直接催化分解中的关键作用。在裸露的CEO2样品中，通过通过降水方法制备的样品获得了最佳性能，然后进行外观进行逐拟，而商业CEO2的性能最低。所有裸氧化物均表现出低N2O转化率，在600华氏度时永远不会超过40％。在CuO-CEO2氧化物中，通过共沉淀制备的人观察到最佳性能，在550度处达到完整的N2O转换。在存在下。在进料流中过量的氧气中，观察到轻微的降解，而DEN（2）O的序列保持不变。与所有其他材料相比，通过沉淀制备的Cu-CE混合氧化物的优势主要归因于其出色的氧化还原性能，这些特性与CE4+/CE3+和CU2+/CU+/CU+氧化还原对有关。提出了用于N2O催化分解的氧化还原机制，涉及Cu+位点上的N2O吸附及其通过Cu-Ceria相互作用的再生。

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