Perovskites as Alternatives to Noble Metals in Automotive Exhaust Abatement: Activation of Oxygen on LaCrO3 and LaMnO3
Perovskites as Alternatives to Noble Metals in Automotive Exhaust Abatement: Activation of Oxygen on LaCrO3 and LaMnO3
复制标题
钙钛矿作为贵金属替代品用于汽车尾气治理：LaCrO3 和 LaMnO3 上的氧活化
DOI：
10.1007/s11244-018-1120-1
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发表时间：
2018
影响因子：
3.6
通讯作者：
A. Glisenti
中科院分区：
文献类型：
--
作者：
G. Peron;A. Glisenti
在这项贡献中，钙钛材料已被测试作为贵金属的替代品，用于汽车尾气减排装置。材料选用lamno3和lacro3。采用x射线衍射、扫描电镜、BET比表面积、程序升温还原和x射线光电子能谱对样品进行了表征。用10%的o2和0.5%的NO氧化烟灰，用1%的CO还原1%的NO，证明了lamno3是氧化反应的良好催化剂，而lacro3更适合于还原反应。TPR和XPS分析表明lamno3比LaCrO3具有更强的氧交换能力，而LaCrO3的还原性较差，并能强键吸附氧。在钙钛晶格的a位用K取代20%的La后，两种催化剂的活性都有所提高。然而，在LaCrO3的情况下，这导致了较慢的反应过程。NO还原试验清楚地表明，含cr的钙钛矿更适合于还原反应，而mn基材料则是氧化应用的良好选择。正如XPS和TPR结果所显示的那样，这可能与表面氧性质和大块氧迁移率有关。
In this contribution, perovskitic materials have been tested as substitutes of noble metals in automotive exhaust abatement devices. LaMnO3and LaCrO3were the chosen materials. Samples were characterized by means of X-ray diffraction, scanning electron microscopy, BET surface area, temperature programmed reduction and X-ray photoelectron spectroscopy. Reactions tested have been soot oxidation by 10% O2and 0.5% NO and stoichiometric 1% NO reduction by 1% CO. LaMnO3has proved to be a good catalyst for oxidation reactions, whereas LaCrO3is more suitable for reduction reactions. TPR and XPS analysis have shown a greater oxygen exchange capability in LaMnO3than in LaCrO3, which is less reducible and strongly bonds adsorbed oxygen. Substitution of 20% La in the A-site of the perovskitic lattice with K has increased activity of both catalysts. In the case of LaCrO3,however, this has lead to a slower reaction course. NO reduction test clearly indicates that Cr-containing perovskite is more suitable for reduction reactions, whereas Mn-based materials are a good choice for oxidative applications. This can relate to superficial oxygen properties and bulk oxygen mobility, as shown by XPS and TPR results.