DRIFTS-XANES study of Pd -Ni / (Ce,Zr )Ox/Al2O3 model automotive catalysts
DRIFTS-XANES study of Pd -Ni / (Ce,Zr )Ox/Al2O3 model automotive catalysts
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DOI：
10.1016/j.cattod.2006.07.059
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发表时间：
2007-08
期刊：
影响因子：
5.3
通讯作者：
A. Martínez-Arias;M. Fernández-García;A. Hungría;A. Iglesias-Juez;J. Anderson
中科院分区：
文献类型：
--
作者：
A. Martínez-Arias;M. Fernández-García;A. Hungría;A. Iglesias-Juez;J. Anderson
研究了新鲜和热老化状态下的Pd-Ni/Al_2O_3和（Ce，Zr）Ox/Al_2O_3催化剂，主要目的是确定Ni和Ce-Zr复合氧化物对CO和C_3H_6氧化以及NO还原反应活性的影响。为此，结合在反应条件下记录的DRIFTS和XANES光谱分析催化活性结果，以获得关于在反应过程中催化剂中发生的过程的信息。虽然镍诱导促进钯和Ce-Zr混合氧化物之间形成接触通常增强催化剂的CO氧化性能，但其结果不利于NO还原活性。这与在存在这种接触的情况下，对于相对相似的颗粒尺寸，实现最活性的金属钯状态的难度更高有关。比较DRIFTS光谱下的各种反应物的混合物和新鲜和老化的系统之间示出以一种独特的方式解释的烃类自中毒和烧结的催化剂中的活性组分的有害催化作用。
Pd-Ni catalysts supported on Al2O3and (Ce,Zr)Ox/Al2O3, both in fresh and thermally aged states, were examined with the main aim of determining the effects of Ni and Ce-Zr mixed oxide on the catalytic activity for CO and C3H6oxidation, and NO reduction reactions under stoichiometric conditions. For this purpose, catalytic activity results were analysed in conjunction with DRIFTS and XANES spectra recorded under reaction conditions to obtain information on the processes occurring in the catalysts during the course of the reactions. While a nickel-induced promotion of the formation of contacts between palladium and the Ce-Zr mixed oxides generally enhances the CO oxidation performance of the catalyst, it results detrimental to the NO reduction activity. This has been related to the higher difficulty in achieving the most active metallic palladium state for comparatively similar particle sizes in the presence of such contacts. Comparison of DRIFTS spectra under various reactant mixtures and between fresh and aged systems was shown to explain in a unique way the detrimental catalytic effects of hydrocarbon self-poisoning and sintering of the active components in the catalysts.