Structure and catalytic property of CeO2-ZrO2-Fe2O3 mixed oxide catalysts for diesel soot combustion: Effect of preparation method
来源期刊：JOURNAL OF RARE EARTHS2014年第9期
论文作者：顾振华 桑秀丽 王华 李孔斋
文章页码：817 - 823
摘 要：A series of Ce0.5Fe0.30Zr0.20O2 catalysts were prepared by different methods（co-precipitations method, citric acid sol-gel method, impregnation method, physical mixed method, and hydrothermal method） and characterized by X-ray diffraction（XRD）, Raman spectroscopy, Brunauer-Emmett-Teller（BET） and H2-TPR measurements. Potential of the catalysts in the soot oxidation was evaluated in a temperature-programmed oxidation（TPO） apparatus. The results showed that all the Fe3+ and Zr4+ were incorporated into ceria lattice to form a pure Ce-Fe-Zr-O solid solution for the co-precipitation sample, but two kinds of Fe phases existed in the Ce-Fe-Zr-O catalysts prepared by other methods: Fe3+ incorporated into CeO2 lattice and dispersed Fe2O3 clusters. The free Fe2O3 clusters could improve the activity of catalysts for soot oxidation comparing with the pure Ce-Fe-Zr-O solid solution owing to the synergetic effect between free Fe2O3 and surface oxygen vacancies. In addition, the activity of catalysts strongly relied on the surface reducibility of free Fe2O3 particles. Holding both abundant free Fe2O3 particles and high oxygen vacancy concentration, the hydrothermal Ce0.5Fe0.3Zr0.2O2 catalyst presented the lowest Ti（251 °C, ignition temperature of soot oxidation） and Tm（310 °C, maximum oxidation rate temperature） for soot combustion（with tight-contact between soot and catalysts） among the five samples. Even after aging at 800 °C for 10 h, the Ti and Tm were still relatively low, at 273 and 361 °C, respectively, indicating high catalytic stability.
顾振华1，桑秀丽2，王华3，李孔斋3
1. Oxbridge College Kunming University of Science and Technology2. Quality Development Institute of Kunming University of Sci-ence and Technology3. Engineering Research Center of Metallurgical Energy Conservation and Emission Reduction Ministry of Ed-ucation Kunming University of Science and Technology
摘 要：A series of Ce0.5Fe0.30Zr0.20O2 catalysts were prepared by different methods（co-precipitations method, citric acid sol-gel method, impregnation method, physical mixed method, and hydrothermal method） and characterized by X-ray diffraction（XRD）, Raman spectroscopy, Brunauer-Emmett-Teller（BET） and H2-TPR measurements. Potential of the catalysts in the soot oxidation was evaluated in a temperature-programmed oxidation（TPO） apparatus. The results showed that all the Fe3+ and Zr4+ were incorporated into ceria lattice to form a pure Ce-Fe-Zr-O solid solution for the co-precipitation sample, but two kinds of Fe phases existed in the Ce-Fe-Zr-O catalysts prepared by other methods: Fe3+ incorporated into CeO2 lattice and dispersed Fe2O3 clusters. The free Fe2O3 clusters could improve the activity of catalysts for soot oxidation comparing with the pure Ce-Fe-Zr-O solid solution owing to the synergetic effect between free Fe2O3 and surface oxygen vacancies. In addition, the activity of catalysts strongly relied on the surface reducibility of free Fe2O3 particles. Holding both abundant free Fe2O3 particles and high oxygen vacancy concentration, the hydrothermal Ce0.5Fe0.3Zr0.2O2 catalyst presented the lowest Ti（251 °C, ignition temperature of soot oxidation） and Tm（310 °C, maximum oxidation rate temperature） for soot combustion（with tight-contact between soot and catalysts） among the five samples. Even after aging at 800 °C for 10 h, the Ti and Tm were still relatively low, at 273 and 361 °C, respectively, indicating high catalytic stability.
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