Cu/Al2O3 catalysts for soot oxidation: Copper loading effect
Cu/Al2O3 catalysts for soot oxidation: Copper loading effect
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DOI：
10.1016/j.apcatb.2008.05.019
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发表时间：
2008-12-01
影响因子：
22.1
通讯作者：
Illan-Gomez, M. J.
中科院分区：
文献类型：
--
作者：
Lopez-Suarez, F. E.;Bueno-Lopez, A.;Illan-Gomez, M. J.
金属负载量为 0.64 至 8.8 wt.% 的 Cu/Al2O3 催化剂已通过不同技术制备和表征：-196 ℃ 下的 N-2 吸附（BET 表面积）、ICP（铜负载量）、XRD、N2O 选择性铜表面氧化（铜分散体）、TPR-H-2（氧化还原性能）和 XPS（铜表面物质）。烟灰氧化催化活性已在空气和 NOx/O-2 中进行了测试。空气中的活性取决于易还原的 Cu(II) 物质的量，这些物质在 TPR-H-2 条件下在 275 摄氏度左右被还原。最活跃的Cu(II)物种的数量随着铜负载量从Cu_1%增加到Cu_5%而增加，并且对于更高的铜负载量几乎保持恒定。在NOx存在下，该机理的第一步是NO氧化成NO2，并且该反应的催化活性取决于铜负载量。对于铜负载量在Cu_1%和Cu_5%之间的催化剂，NOx存在下烟灰氧化的催化活性取决于NO2的形成。对于铜负载量较高的催化剂，由于模型烟灰在最大 NO2 产生温度下的反应性较低，因此不会遵循这种趋势。无论铜负载量如何，所有催化剂都提高了在空气和 NOx/O-2 下形成烟灰氧化产物 CO2 的选择性。 (C) 2008 Elsevier B.V. 保留所有权利。
Cu/Al2O3 catalysts with metal loading from 0.64 to 8.8 wt.% have been prepared and characterized by different techniques: N-2 adsorption at -196 degrees C (BET surface area), ICP (Cu loading), XRD, selective copper surface oxidation with N2O (Cu dispersion), TPR-H-2 (redox properties), and XPS (copper surface species). The catalytic activity for soot oxidation has been tested both in air and NOx/O-2. The activity in air depends on the amount of easily-reduced Cu(II) species, which are reduced around 275 degrees C under TPR-H-2 conditions. The amount of the most active Cu(II) species increases with the copper loading from Cu_1% to Cu_5% and remains almost constant for higher copper loading, In the presence of NOx, the first step of the mechanism is NO oxidation to NO2, and the catalytic activity for this reaction depends on the copper loading. For catalysts with copper loading between Cu_1% and Cu_5%, the catalytic activity for soot oxidation in the presence of NOx depends on NO2 formation. For catalysts with higher copper loading this trend is not followed because of the low reactivity of model soot at the temperature of maximum NO2 production. Regardless the copper loading, all the catalysts improve the selectivity towards CO2 formation as soot oxidation product both under air and NOx/O-2. (C) 2008 Elsevier B.V. All rights reserved.