Modification of Cu/ZSM-5 catalyst with CeO2 for selective catalytic reduction of NOx with ammonia
来源期刊：Journal of Rare Earths2016年第10期
论文作者：刘雪松 吴晓东 翁端
文章页码：1004 - 1009
摘 要：Cu/ZSM-5 and CeO2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO2 was found to enhance the NOx selective catalytic reduction（SCR） activity of the catalyst at low temperatures, but the high-temperature activity was weakened. The catalysts were characterized by X-ray diffraction（XRD）, nitrogen physisorption, inductively coupled plasma optical emission spectrometry（ICP-OES）, X-ray photoelectron spectroscopy（XPS）, electron paramagnetic resonance（EPR）, H2 temperature-programmed reduction（TPR） and NH3 temperature-programmed desorption（TPD）. The results showed that more CuO clusters instead of isolated Cu2+ species were obtained on the modified catalyst. These active CuO clusters, as well as the Cu-Ce synergistic effect, improved the redox property of the catalyst and low-temperatures SCR activity via promoting the oxidation of NO to NO2 and fast SCR reaction. The loss in high-temperatures activity was attributed to the enhanced competitive oxidation of NH3 by O2 and decreased surface acidity of the catalyst.
刘雪松1,2，吴晓东1,2，翁端1,2
1. Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University2. Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University
摘 要：Cu/ZSM-5 and CeO2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO2 was found to enhance the NOx selective catalytic reduction（SCR） activity of the catalyst at low temperatures, but the high-temperature activity was weakened. The catalysts were characterized by X-ray diffraction（XRD）, nitrogen physisorption, inductively coupled plasma optical emission spectrometry（ICP-OES）, X-ray photoelectron spectroscopy（XPS）, electron paramagnetic resonance（EPR）, H2 temperature-programmed reduction（TPR） and NH3 temperature-programmed desorption（TPD）. The results showed that more CuO clusters instead of isolated Cu2+ species were obtained on the modified catalyst. These active CuO clusters, as well as the Cu-Ce synergistic effect, improved the redox property of the catalyst and low-temperatures SCR activity via promoting the oxidation of NO to NO2 and fast SCR reaction. The loss in high-temperatures activity was attributed to the enhanced competitive oxidation of NH3 by O2 and decreased surface acidity of the catalyst.
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