The activity and characterization of MnO_x-CeO₂-ZrO₂/纬-Al₂O₃ catalysts for low temperature selective catalytic reduction of NO with NH₃

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• 作者：Fan Cao ; Jun Xiang ; ^{xiangjun_sklcc@hotmail.com" class="auth_mail} ; Sheng Su ; ^{susheng_sklcc@hotmail.com" class="auth_mail} ; Pengying Wang ; Lushi Sun ; Song Hu ; Siyuan Lei
• 关键词：Low temperature SCR ; MnOx&ndash ; CeO2&ndash ; ZrO2/纬-Al2O3 ; Mechanism study ; In situ DRIFTS
• 刊名：Chemical Engineering Journal
• 出版年：1 May, 2014
• 年：2014
• 卷：243
• 期：Complete
• 页码：347-354
• 全文大小：1990 K

文摘

MnO_x-CeO₂-ZrO₂/纬-Al₂O₃ catalyst was prepared by the sol-gel method and then investigated on the selective catalytic reduction (SCR) of NO_x (NO and NO₂) by NH₃. The catalytic activity was enhanced by the addition of Zr in the broad temperature range of 100-400 掳C. This catalyst could also be well-behaved under high GHSV and in the presence of SO₂ and H₂O. The XRD and XPS results showed that the Zr⁴⁺ ions incorporated into the CeO₂ crystal lattice and formed the solid solution, resulting that the BET surface area and pore volume of this catalyst increased obviously. The detailed SCR mechanism was researched using the in situ DRIFTS. It showed that NO could be adsorbed on the catalyst and formed different kinds of nitrates at 150 掳C, which almost converted to the stable bidentate and bridged nitrates in the presence of O₂. NH₃ could be adsorbed on both Lewis sites (coordinated NH₃ species) and Br酶nsted sites () at 150 掳C. These adsorption products were enhanced by introducing O₂. The results of the SCR reaction on the catalyst indicated that the reaction route could follow the Eley-Rideal mechanism as NH₃ pre-adsorbed on the catalyst, it could also follow the Langmuir-Hinshelwood mechanism when NO pre-adsorbed on the catalyst.