氮氧化物
吸附
X射线光电子能谱
铈
化学
漫反射红外傅里叶变换
傅里叶变换红外光谱
解吸
分析化学(期刊)
材料科学
无机化学
化学工程
光催化
催化作用
有机化学
燃烧
工程类
作者
Miao Yu,Yan Ding,Xiang Yu,Shu Yan,Meiqing Shen,Jianqiang Wang,Jun Wang,Gurong Shen
标识
DOI:10.1016/j.jre.2023.06.005
摘要
Ce/BEA has great potential as a passive NOx absorber (PNA) to reduce the NOx emissions during the cold start phase especially in diesel engine for its high resistance to CO and suitable NOx desorption temperature range. However, as a novel material, its physical and chemical properties still remain unknown. In this work, Ce/BEA was synthesized by ion-exchange method to identify the active species in NOx adsorption, compared with aggregated Ce species in Ce/SiAlOx prepared by impregnation method. X-ray diffraction (XRD), high resolution-transmission electron microscopy (HR-TEM) and aberration-corrected-scanning transmission electron microscopy (AC-STEM) were performed to confirm the isolated single atom formation of Ce species in Ce/BEA. UV–vis diffraction reflection spectra (DRS) and X-ray photoelectron spectroscopy (XPS) were conducted to find the difference of chemical environment between the isolated Ce species and aggregated ones. PNA performance evaluation and temperature programmed reduction of hydrogen (H2-TPR) results show the high NOx storage capacity and active oxygen species quantity in Ce/BEA. It is also found that the main NOx adsorption species are Ce4+–O* rather than Ce3+. NOx-diffuse reflectance infrared Fourier transform spectroscopy (NOx-DRIFTS) confirms that the bidentate nitrite species are the critical NOx adsorption intermediates and the conception of NOx adsorption and desorption processes is proposed.
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