中国环境科学

作者：陈曦, 王小燕, 李巧艳, 王梦雪, 梁美生

单位：1. 太原理工大学环境科学与工程学院, 大气复合污染识别与控制山西省重点实验室, 山西 晋中 030600;2. 山西省生态环境规划和技术研究院, 山西 太原 030009

关键词：NH3-SCR,钾离子,Mn-Ce固溶体,酸性,活性氧

基金：国家自然科学基金(22376156);山西省基础研究计划项目(20210302124478,202203021211140);太原市生态环境局委托项目(RH2400000291)

In this work, K ions were successfully introduced into the lattice of as-prepared Mn-Ce solid solutions (MnCeOx) by a hydrothermal method, and that was applied in NH3-SCR. The Mn-O bonding was deeply weakened, leading to a better reducibility and oxygen desorption capacity of the K-contained catalysts according to H2-TPR and O2-TPD. Furthermore, the introduction of K ions could facilitate the adsorptive capacity of Brønsted acid sites for NH3 due to the enhanced electron transfer between Mn/Ce elements according to the characterizations of XPS, NH3-TPD and in situ DRIFT. Then, the synergy among the acidity and adsorbed active oxygen could promote the activities of catalyst MnCeKyOx on NH3-SCR. With the proportion of 1:5:5 for the amounts of K, Ce and Mn elements, the best performed catalyst MnCeK1Ox could achieve 94.6% conversion of NO at a lower temperature of 120℃. The broader temperature ranging from 40~260℃ is beneficial for the conversion of NO at many conditions. Finally, in situ DRIFTs of NH3 and NO adsorption on MnCeOx and MnCeK1Ox suggested that the reaction was more sensitive to the adsorption of NH3 than NO. For MnCeOx, NH3 was primarily bound on Lewis then Brønsted acid sites, resulting in the rapid aggregation of both monodentate and bidentate nitrate. For MnCeK1Ox, the simultaneous adsorption of NH3 on Lewis and Brønsted acid sites led to less accumulation of intermediates like bidentate nitrate. The results indicated that the introduction of K ions could efficiently improve the activity of Mn-Ce solid solution in NH3-SCR reaction.

来源：2024年第11期

《中国环境科学》期刊编辑部

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