A basic comprehensive study on synergetic effects among the metal oxides in CeO2-WO3/TiO2 NH3-SCR catalyst
A basic comprehensive study on synergetic effects among the metal oxides in CeO2-WO3/TiO2 NH3-SCR catalyst
复制标题
CeO2-WO3/TiO2 NH3-SCR催化剂中金属氧化物协同效应的基础综合研究
DOI：
10.1016/j.cej.2020.127833
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发表时间：
2021-06-13
影响因子：
15.1
通讯作者：
Wu, Xiaodong
中科院分区：
文献类型：
--
作者：
Liu, Xuesong;Jiang, Peng;Wu, Xiaodong
采用湿法浸渍(CEW/Ti-I)和机械混合(Ce/W/Ti-M)法制备了两种Ce-W-Ti复合氧化物催化剂。CEW/Ti-I催化剂在200-550℃下表现出80%以上的NOx转化率和近100%的N-2选择性，这与活性CeO2和酸性WO_3在Ti02上的高分散性以及不同组分之间的协同作用有关。进行了X-射线衍射、拉曼光谱、氮气物理吸附、X-射线光电子能谱、氢气程序升温还原、氨气程序升温脱附和红外光谱等测试。结果表明，固溶体的形成以及催化剂的高比表面积增加了催化剂中Ce3+、氧空位和酸中心的数量。这拓宽了NH3-SCR反应的操作温度窗口，通过促进低温下的快速SCR反应和抑制高温下NH3的非选择性氧化，提高了N-2的选择性。
Two Ce-W-Ti mixed oxide catalysts were prepared by wet impregnation (CeW/Ti-I) and mechanical mixing (Ce/W/Ti-M) methods. CeW/Ti-I catalyst exhibits over 80% NOx conversion and nearly 100% N-2 selectivity at 200-550 degrees C. The superior catalytic performance is associated with the high dispersion of active CeO2 and acidic WO3 on TiO2 and the synergistic effects among different components. The X-ray Diffraction, Raman spectroscopy, Nitrogen physisorption, X-ray photoelectron spectroscopy, H-2 temperature-programmed reduction, temperature-programmed desorption of ammonia and infrared spectroscopy were performed. It is found that the formation of solid solutions, as well as the high specific surface area, would increase the amounts of Ce3+, oxygen vacancies and acid sites in the catalyst. These broaden the operating temperature window of NH3-SCR reaction and enhance the N-2 selectivity by facilitating "fast SCR" reaction at low temperatures and inhibiting the unselective oxidation of NH3 at high temperatures.