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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
European Journal of Inorganic Chemistry
(
IF
2.3
)
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
- SHU centre of green urban mining & industry ecology; School of Environmental and Chemical Engineering; Shanghai University; No. 333 Nanchen Rd. 200444 Shanghai PR China
- CAS Key Laboratory of Carbon Materials; Institute of Coal Chemistry; Chinese Academy of Sciences; 030001 Taiyuan P. R. China
- National Engineering Laboratory for Carbon Fiber Technology; Institute of Coal Chemistry; Chinese Academy of Sciences; 030001 Taiyuan P. R. China
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 (VO–s) and bulk oxygen vacancies (VO–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 VO–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 VO–b instead. These results originate from the fact that the generation and delivery of active oxygen are affected by combinations of VO–s and VO–b rather than just one of them. The moderate concentration of VO–s and sufficient concentration of VO–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.
中文翻译:
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
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。
更新日期:2018-06-22