Mechanism of the Selective Catalytic Oxidation of Slip Ammonia over Ru-Modified Ce-Zr Complexes Determined by in Situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy
Mechanism of the Selective Catalytic Oxidation of Slip Ammonia over Ru-Modified Ce-Zr Complexes Determined by in Situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy
复制标题
原位漫反射红外傅里叶变换光谱测定Ru修饰Ce-Zr配合物选择性催化氧化滑移氨的机理
DOI：
10.1021/es502369f
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发表时间：
2014-10-21
影响因子：
11.4
通讯作者：
Yan, Naiqiang
中科院分区：
文献类型：
--
作者：
Chen, Wanmiao;Ma, Yongpeng;Yan, Naiqiang
燃煤烟气中氮氧化物选择性催化还原 (SCR) 产生的逃逸氨可能导致公用设施恶化，甚至造成环境问题。为了实现滑氨的选择性催化氧化（SCO），制备了Ru修饰的Ce-Zr固溶体催化剂，并在不同条件下进行了评价。结果发现，Ru/Ce0.6Zr0.4O2(聚乙烯吡咯烷酮(PVP))催化剂表现出显着的催化活性，在NOx和SO2共存的情况下，逃逸氨几乎完全被去除。有趣的是，SO2对NH3氧化的影响是双面的，并且在SO2和NH3存在下所得产物的N-2选择性高达100%。采用多种技术研究了NH3在Ru/Ce0.6Zr0.4O2(PVP)上的SCO机理，结果表明NH3氧化遵循内部SCR(iSCR)机制。吸附的氨首先被活化并与晶格氧原子反应形成-HNO中间体。然后，-HNO主要与O-2中的原子氧反应形成NO。同时，形成的NO与-NH2相互作用生成N-2，副产物N2O，但SO2的存在可以有效抑制N2O的产生。
The slip ammonia from selective catalytic reduction (SCR) of NOx in coal-fired flue gas can result in deterioration of the utilities or even the environmental issues. To achieve selective catalytic oxidation (SCO) of slip ammonia, Ru-modified Ce-Zr solid solution catalysts were prepared and evaluated under various conditions. It was found that the Ru/Ce0.6Zr0.4O2(polyvinylpyrrolidone (PVP)) catalyst displayed significant catalytic activity and the slip ammonia was almost completely removed with the coexistence of NOx and SO2. Interestingly, the effect of SO2 on NH3 oxidation was bifacial, and the N-2 selectivity of the resulting products was as high as 100% in the presence of SO2 and NH3. The mechanism of the SCO of NH3 over Ru/Ce0.6Zr0.4O2(PVP) was studied using various techniques, and the results showed that NH3 oxidation follows an internal SCR (iSCR) mechanism. The adsorbed ammonia was first activated and reacted with lattice oxygen atoms to form an -HNO intermediate. Then, the -HNO mainly reacted with atomic oxygen from O-2 to form NO. Meanwhile, the formed NO interacted with -NH2 to N-2 with N2O as the byproduct, but the presence of SO2 can effectively inhibit the production of N2O.