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论文类型：期刊论文

发表时间：2016-12-01

发表刊物：MICROPOROUS AND MESOPOROUS MATERIALS

收录刊物：SCIE、EI、Scopus

卷号：236

页面范围：211-217

ISSN号：1387-1811

关键字：Al-rich Beta; Cu-Fe-Beta; NH3-SCR; Synergistic effect; Sulfur resistance

摘要：Copper and iron bimetal modified Al-rich Beta zeolites from template-free synthesis were prepared for selective catalytic reduction (SCR) of NOX with NH3 in exhaust gas streams. Comparing to the Cu-based and Fe-based mono-component Beta catalysts, Cu(3.0)-Fe(1.3)-Beta bi-component catalyst shows better low-temperature activity and wider reaction-temperature window. Over 80% of NO conversion can be achieved at the temperature region of 125-500 degrees C. Due to the synergistic effect of copper and iron evidenced by XRD, UV-Vis-NIR, EPR and XPS measurements, the dispersion state of active components as well as the ratio of Cu2+/Cu+ and Fe3+/Fe2+ were improved over Cu(3.0)-Fe(1.3)-Beta. Isolated Cu2+ and Fe3+ ions which located at the exchange sites could be the active species at the low-temperature region, while FeOX cluster species may be more important to the high-temperature activity. During the test of sulfur resistance, Fe-containing samples including Cu(3.0)-Fe(1.3)-Beta and Fe(2.7)-Beta-4 present better performance compared to Cu(4.1)-Beta-4. Deactivation of Cu-based catalyst is attributed to the easier deposition of sulfates over the surface according to the results of TGA coupled with TPD experiments. (C) 2016 Elsevier Inc. All rights reserved.