CeO2或Ag / CeO2上的碳烟氧化：大量氧空位和表面氧空位对催化剂活性和稳定性的影响,European Journal of Inorganic Chemistry

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CeO2或Ag / CeO2上的碳烟氧化：大量氧空位和表面氧空位对催化剂活性和稳定性的影响
European Journal of Inorganic Chemistry ( IF 2.2 ) Pub Date : 2018-06-22 , DOI: 10.1002/ejic.201800423
Shijie Wu _{1,

2} , Yu Yang _{2,

3} , Chunxiang Lu _{2,

3} , Yuanyuan Ma _{2,

3} , Shuxia Yuan _{2,

3} , Guangren Qian ₁

Affiliation

合成了三种类型的CeO ₂，并且通过使用这些CeO ₂类型作为载体浸渍Ag ，制备了三种类型的Ag / CeO ₂。它们的形貌和结构通过SEM，HRTEM，氮吸附-解吸等温线和H ₂ -TPR还原进行表征，表明有效的烟灰-催化剂接触和尺寸分布以及Ag的化学状态是相同的。使用XPS和拉曼光谱法分别研究了表面氧空位（VO _-s）和本体氧空位（VO _-b）。CeO ₂催化剂的活性与表面化学吸附的氧有关，而Ag / CeO ₂的活性与表面化学吸附的氧有关。通过V的决定_Ô-S富氧条件下，Ag粒子的附近。当将气氛切换到贫氧条件下时，Ag / CeO ₂的活性由VO _b控制。这些结果源于以下事实：活性氧的生成和传递受V _O–s和V _O–b的组合影响，而不仅仅是其中之一。中等浓度的V _O–s和足够的V _O–b有利于在缺氧条件下提高Ag / CeO _2的催化活性。在这项工作中，Ag负载在50°C下制备的CeO _2上（定义为Ag / CeO ₂‐50）被认为是用于汽油微粒过滤器的潜在催化剂。

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Soot Oxidation over CeO2 or Ag/CeO2: Influences of Bulk Oxygen Vacancies and Surface Oxygen Vacancies on Activity and Stability of the Catalyst

Three types of CeO₂ were synthesized and through impregnation of Ag employing these CeO₂ types as supports, three kinds of Ag/CeO₂ were prepared. Their morphologies and structures were characterized by SEM, HRTEM, nitrogen adsorption–desorption isotherms, and H₂‐TPR reduction, indicating that the effective soot‐catalyst contact and size distribution as well as the chemical state of Ag were identical. Surface oxygen vacancies (V_O–s) and bulk oxygen vacancies (V_O–b) were investigated by using XPS and Raman spectroscopy, respectively. The activities of the CeO₂ catalysts are related to surface chemisorbed oxygen, while the activities of Ag/CeO₂ are decided by V_O–s near the Ag particles under oxygen‐rich conditions. When switching the atmosphere to oxygen‐poor conditions, the activities of Ag/CeO₂ are controlled by V_O–b instead. These results originate from the fact that the generation and delivery of active oxygen are affected by combinations of V_O–s and V_O–b rather than just one of them. The moderate concentration of V_O–s and sufficient concentration of V_O–b are favorable for increasing catalytic activity under oxygen‐poor conditions for Ag/CeO₂. In this work, Ag loaded on CeO₂, prepared at 50 °C, (defined as Ag/CeO₂‐50) can be considered as a prospective catalyst for use in gasoline particulate filters.

更新日期：2018-06-22

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