物理化学学报 >> 2008, Vol. 24 >> Issue (11): 2059-2064.doi: 10.3866/PKU.WHXB20081121

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Cu催化水煤气的变换反应机理

毛江洪; 倪哲明; 潘国祥; 胥倩   

  1. 浙江工业大学化学工程与材料学院, 杭州310032
  • 收稿日期:2008-07-22 修回日期:2008-08-21 发布日期:2008-11-10
  • 通讯作者: 倪哲明 E-mail:jchx@zjut.edu.cn

Mechanism of the Copper-Catalyzed Water Gas Shift Reaction

MAO Jiang-Hong; NI Zhe-Ming; PAN Guo-Xiang; XU Qian   

  1. College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, P. R. China
  • Received:2008-07-22 Revised:2008-08-21 Published:2008-11-10
  • Contact: NI Zhe-Ming E-mail:jchx@zjut.edu.cn

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摘要： 采用密度泛函理论(DFT), 对Cu催化水煤气变换反应三种可能的微观机理进行了理论研究. 在GGA-PW91理论水平下优化了反应通道上各驻点(反应物、中间体、过渡态和产物)的几何构型, 并通过频率分析对过渡态进行了验证. 研究结果表明, 甲酸根机理的可能性最小, 羧基机理与氧化还原机理的可能性较大, 且与氧化还原机理相比, 羧基机理因在反应过程中有中间体COOH(s)生成, 且它与OH(s)发生歧化反应仅需越过3.8 kJ·mol-1的活化能垒, 所以反应更易遵循这条路径进行.

关键词: 水煤气变换反应, 反应机理, 密度泛函理论, 过渡态

Abstract: A detailed density functional theory (DFT) investigation revealed three possible micro-mechanisms of the water-gas shift reaction catalyzed by copper. Geometries of stationary points (reactants, intermediates, transition states and products) were optimized with the self-consistent Perdew-Wang-91 generalized gradient approximation (GGA-PW91) method. All transition states were verified by the frequency analysis method. Results showed that the formate mechanismhad a lowprobability, while the carboxyl mechanismand the redox mechanismwere more probable. During the carboxyl mechanism, the intermediate COOH(s) was formed followed by its decomposition via disproportionation with OH (s). The calculated activation energy barrier for the carboxyl mechanism was 3.8 kJ·mol-1, which was lower than that for the redox mechanism.

Key words: Water gas shift reaction, Reaction mechanism, Density functional theory, Transition state

MSC2000: 

  • O641