Insight into the Mechanism of Selective Catalytic Reduction of NOx by Propene over the Cu/Ti0.7Zr0.3O2 Catalyst by Fourier Transform Infrared Spectro

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• 作者：Jie Liu ; Xinyong Li ; Qidong Zhao ; Ce Hao ; Dongke Zhang
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：May 7, 2013
• 年：2013
• 卷：47
• 期：9
• 页码：4528-4535
• 全文大小：523K
• 年卷期：v.47,no.9(May 7, 2013)
• ISSN：1520-5851

文摘

The mechanism of selective catalytic reduction of NO_x by propene (C₃H₆-SCR) over the Cu/Ti_0.7Zr_0.3O₂ catalyst was studied by in situ Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT) calculations. Especially, the formation and transformation of cyanide (鈭扖N species) during the reaction was discussed. According to FTIR results, the excellent performance of the Cu/Ti_0.7Zr_0.3O₂ catalyst in C₃H₆-SCR was attributed to the coexistence of two parallel pathways to produce N₂ by the isocyanate (鈭扤CO species) and 鈭扖N species intermediates. Besides the hydrolysis of the 鈭扤CO species, the reaction between the 鈭扖N species and nitrates and/or NO₂ was also a crucial pathway for the NO reduction. On the basis of the DFT calculations on the energy of possible intermediates and transition states at the B3LYP/6-311 G (d, p) level of theory, the reaction channel of 鈭扖N species in the SCR reaction was identified and the role of 鈭扖N species as a crucial intermediate to generate N₂ was also confirmed from the thermodynamics view. In combination of the FTIR and DFT results, a modified mechanism with two parallel pathways to produce N₂ by the reaction of 鈭扤CO and 鈭扖N species over the Cu/Ti_0.7Zr_0.3O₂ catalyst was proposed.