Studies on three-way catalysis with supported gold catalysts. Influence of support and water content in feed
Studies on three-way catalysis with supported gold catalysts. Influence of support and water content in feed
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DOI：
10.1016/j.apcatb.2016.10.017
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发表时间：
2017-04
影响因子：
22.1
通讯作者：
V. Ulrich;B. Moroz;I. Sinev;Pavel Pyriaev;V. Bukhtiyarov;W. Grünert
中科院分区：
文献类型：
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作者：
V. Ulrich;B. Moroz;I. Sinev;Pavel Pyriaev;V. Bukhtiyarov;W. Grünert
通过将由 1.1% CO、0.1% 丙烯、0.1% NO、O2（0.95% - 化学计量、0.85% - 富水或 1.05% - 贫水）和水（10% 或无）组成的模型废气转化为负载在 Al2O3、La-Al2O3 上的含有 1-2 wt-% Au 的催化剂来检验金在三元催化反应中的潜力。 TiO2 和 CeZrOx 载体。为了进行比较，CO 和丙烯也在没有其他反应物的情况下与氧气进行化学计量反应，同样，还检查了 CO 还原 NO。结果发现，丙烯对CO氧化有很强的毒害作用，但中毒效应的强度取决于载体（Al2O3>La-Al2O3>TiO2>CeZrOx）。干饲料中中毒最严重，但湿饲料中中毒程度有所减轻。 NO 在 TWC 混合物和二元进料中转化率都很低。在模型排气中，NO 转化导致低温下大量 N2O 形成，但 N2 的选择性随温度升高而增加。尽管受到丙烯中毒，Au/CeZrOx 在 CO 和丙烯氧化方面的性能优于商业参考催化剂。在 923 K 的潮湿稀空气中煅烧仅对金催化剂造成中度损坏。在Au/CeZrOx上，化学计量进料中的CO氧化根本没有受到显着影响，但丙烯的中毒效应在TWC模型进料中变得更加严重。 1223 K 下的类似处理会对所有涉及的反应和所有支撑物造成不可接受的损害。
The potential of gold for the reactions of three-way catalysis was examined by converting a model exhaust consisting of 1.1% CO, 0.1% propene, 0.1% NO, O2(0.95% - stoichiometric, 0.85% - rich, or 1.05% - lean), and water (10% or none) over catalysts containing 1–2 wt-% Au supported on Al2O3, La-Al2O3, TiO2, and CeZrOxsupports. For comparison, CO and propene were also reacted stoichiometrically with oxygen in absence of further reactants, likewise, reduction of NO with CO was examined. It was found that propene is a strong poison for CO oxidation, but the intensity of the poisoning effect depended on the support (Al2O3> La-Al2O3> TiO2> CeZrOx). The poisoning was strongest in dry feed but was partly alleviated in moist feed. NO was poorly converted both in the TWC mixture and in binary feed. In the model exhaust, NO conversion resulted in significant N2O formation at low temperatures, but selectivity to N2increased with temperature. Despite poisoning by propene, Au/CeZrOxoutperformed a commercial reference catalyst in CO and propene oxidation. Calcination in moist dilute air at 923 K inflicted only moderate damage to the Au catalysts. Over Au/CeZrOx, CO oxidation in stoichiometric feed was not significantly affected at all, but the poisoning effect of propene became more severe in the TWC model feed. Analogous treatment at 1223 K resulted in inacceptable damage to all reactions involved and on all supports.