Surface oxygen species essential for the catalytic activity of Ce-M-Sn (M = Mn or Fe) in soot oxidation
Surface oxygen species essential for the catalytic activity of Ce-M-Sn (M = Mn or Fe) in soot oxidation
复制标题
Ce-M-Sn（M = Mn 或 Fe）烟灰氧化催化活性所必需的表面氧物种
DOI：
10.1039/d0cy02077j
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发表时间：
2021
影响因子：
5
通讯作者：
Hong He
中科院分区：
文献类型：
--
作者：
Meng Wang;Yan Zhang;Yunbo Yu;Wenpo Shan;Hong He
本文采用水热法成功合成了过渡金属（Mn和Fe）掺杂的Ce-Sn纳米棒催化剂。通过程序升温氧化反应试验在松接触条件下评价了所得催化剂的碳烟氧化活性。结果表明，Mn掺杂的Ce-Sn催化剂具有最高的催化活性，其ΔT10、ΔT50和ΔT90分别为56 °C、56.2 °C和45.4 °C，低于Ce0.5Sn0.5O2催化剂。Ce_（0.5）Mn_（0.2）Sn_（0.3）O_2催化剂具有优异的抗水性能。最后，采用XRD、TEM、SEM、BET、H2-TPR、XPS和拉曼光谱等手段对催化剂进行了表征。结果表明，Mn或Fe的掺杂有利于Ce 3+的生成，Ce 3+的生成与表面氧空位有关。表面氧空位有利于促进表面活性氧物种的形成。有趣的是，Ce 3 +/Ce 4+的比例和表面活性氧物种的密度之间存在线性关系。研究还发现，表面活性氧的数量与NO2的利用率呈线性关系，NO2可以在气相中扩散到碳烟中，促进碳烟的氧化。总之，这项研究表明，表面活性氧是至关重要的NO2辅助烟灰氧化。
Herein, transition metal (Mn and Fe)-doped Ce–Sn nanorod catalysts were successfully synthesized via a hydrothermal method. The obtained catalysts were evaluated for soot oxidation activity by temperature programmed oxidation reaction tests under loose contact. It was clearly found that the Mn-doped Ce–Sn catalyst exhibited the highest catalytic activity, with ΔT10, ΔT50 and ΔT90 values of 56 °C, 56.2 °C and 45.4 °C, lower than those of the Ce0.5Sn0.5O2 catalyst. The Ce0.5Mn0.2Sn0.3O2 catalyst also possessed outstanding and stable resistance to H2O. Finally, all the prepared catalysts were characterized by XRD, TEM, SEM, BET, H2-TPR, XPS, and Raman spectroscopy. The results suggested that doping with Mn or Fe was beneficial to the generation of more Ce3+, which was linked to surface oxygen vacancies. Surface oxygen vacancies were beneficial to accelerating the formation of surface-active oxygen species. Interestingly, a linear relationship existed between the Ce3+/Ce4+ ratio and the density of surface-active oxygen species. It was also found that there was a linear relationship between the amount of surface-active oxygen and the utilization efficiency of NO2, which could diffuse into soot in the gas phase to improve soot oxidation. In short, this study demonstrates that surface-active oxygen is crucially important in NO2-assisted soot oxidation.