Ambient Pressure Photoemission Spectroscopy Reveals the Mechanism of Carbon Soot Oxidation in Ceria‐Based Catalysts
Ambient Pressure Photoemission Spectroscopy Reveals the Mechanism of Carbon Soot Oxidation in Ceria‐Based Catalysts
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DOI：
10.1002/cctc.201600615
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发表时间：
2016-09
期刊：
影响因子：
4.5
通讯作者：
L. Soler;A. Casanovas;C. Escudero;V. Pérez-Dieste;E. Aneggi;A. Trovarelli;J. Llorca
中科院分区：
文献类型：
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作者：
L. Soler;A. Casanovas;C. Escudero;V. Pérez-Dieste;E. Aneggi;A. Trovarelli;J. Llorca
消除烟尘是将内燃机对环境的影响降至最低的最重要挑战之一。基于CeO2的催化剂因其在保持结构完整性的同时易于储存和释放氧气的能力而被证明适合于氧化烟尘，尽管它们在涉及两个固相(催化剂和烟灰)和一个气相(氧)的复杂环境中的操作模式尚不完全清楚。在此，我们用近常压光电子能谱研究了工作条件下CeO_2-碳烟和CeO_2-ZrO_2-碳烟混合物的表面/亚表面。消烟途径有两种：一种是在CeO_2-碳烟界面形成氧空位和CeIII；另一种是由气相O2与氧空位反应产生的活性超氧化物物种介导的碳烟表面。这两条路径同时出现，相互促进。
Removing soot is one of the most important challenges in minimizing the impact of combustion engines on the environment. Catalysts based on CeO2 have proved suitable to oxidize soot owing to their capacity to store and release oxygen easily while maintaining structural integrity, although their mode of operation in a complex environment involving two solid phases (catalyst and soot) and a gas phase (oxygen) is not yet fully understood. Herein, we provide a study of the surface/subsurface of ceria–soot and ceria–zirconia–soot mixtures under working conditions by means of near‐ambient‐pressure photoelectron spectroscopy. Soot abatement involves two cooperative routes: one occurring at the ceria–soot interface with formation of oxygen vacancies and CeIII and the other at the surface of soot, mediated by active superoxide species, which result from the reaction between gas‐phase O2 and oxygen vacancies. The two routes occur simultaneously and mutually reinforce each other.