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论文类型：期刊论文

发表时间：2012-12-06

发表刊物：JOURNAL OF PHYSICAL CHEMISTRY C

收录刊物：SCIE、EI、Scopus

卷号：116

期号：48

页面范围：25319-25327

ISSN号：1932-7447

摘要：A series of iron-modified Ce/TiO2 catalysts with different Fe/Ti molar ratios were prepared by an impregnation method and used for selective catalytic reaction (SCR) of NOx with NH3. The Fe-Ce/TiO2 catalyst with a Fe/Ti molar ratio of 0.2 had good low-temperature activity and sulfur-poisoning resistance compared with the Ce/TiO2 catalyst. The introduction of Fe could increase the amount of Ce3+ and chemisorbed oxygen species on the catalyst surface and thereafter generate more ionic NH4+ and in situ formed NO2, respectively. In addition, the dispersion of cerium oxide could be improved by the addition of iron, and no visible phase of iron oxide could be observed at low Fe/Ti molar ratios (<= 0.2). All of these factors played significant roles in the enhanced catalytic activity, especially the low-temperature activity. Furthermore, mechanisms of the SCR reaction and the SO2 poisoning of the Fe(0.2)-Ce/TiO2 catalyst were studied using in situ diffuse reflectance infrared Fourier transform spectroscopy. Coordinated NH3 and ionic NH4+ species as well as adsorbed NO2 might be the key intermediates in the SCR reaction in the relatively low-temperature range. The formation of ammonium sulfate appeared to be the dominant cause for the catalyst deactivation in SO2-containing gases.