物理化学学报 >> 2012, Vol. 28 >> Issue (06): 1455-1460.doi: 10.3866/PKU.WHXB201203303

催化和表面科学 上一篇    下一篇

控制CO选择氧化反应中金催化剂热点形成的新方法

王芳, 王彩红, 李大枝   

  1. 滨州学院化学与化工系, 山东滨州 256603
  • 收稿日期:2011-12-13 修回日期:2012-03-29 发布日期:2012-05-17
  • 通讯作者: 王芳 E-mail:wangfangosso@yahoo.cn
  • 基金资助:

    滨州学院科研基金(2010Y06)资助项目

Novel Method of Controlling Formation of Hot-Spot over Gold Catalysts for CO Oxidation

WANG Fang, WANG Cai-Hong, LI Da-Zhi   

  1. Department of Chemistry & Chemical Engineering, Binzhou University, Binzhou 256603, Shandong Province, P. R. China
  • Received:2011-12-13 Revised:2012-03-29 Published:2012-05-17
  • Contact: WANG Fang E-mail:wangfangosso@yahoo.cn
  • Supported by:

    The project was supported by the Research Fund of Binzhou University, China (2010Y06).

摘要: 采用沉积-沉淀法制备了Al2O3和MOx-Al2O3 (M=Fe, Zn)负载型金催化剂. 室温下对其CO氧化及富氢条件下CO选择氧化催化活性进行了广泛的研究. 催化剂床层温度由热电偶直接测定. 催化剂表面温度与O2/CO的体积比以及CO和H2的浓度密切相关. 在CO氧化反应过程中Au/Al2O3催化剂的温度可高达170°C, 添加FeOx可使其降至55°C. 利用一系列仪器(X 射线衍射仪, X射线光电子能谱仪和透射电镜等)对催化剂的结构进行了表征. 结果显示Al2O3负载型金催化剂热点的形成可以通过添加合适的助剂很好地控制. 助剂的添加能够使催化剂活性中心由金属态Au变为AuIII, 从而导致了CO选择氧化反应机理不同.

关键词: CO氧化, 助剂, 金催化剂, 热点

Abstract: Au catalysts supported on Al2O3 and MOx-Al2O3 (M=Fe and Zn) were prepared by the deposition-precipitation method. Their catalytic activities for CO oxidation in the absence and presence of an H2-rich steam at room temperature were investigated in detail. Catalyst bed temperatures were determined directly by a thermocouple. The catalyst surface temperature depended on the volume ratio of O2/CO, and the concentrations of CO and H2. The temperature on the Au/Al2O3 surface can reach 170°C during CO oxidation, and is decreased to 55°C by addition of FeOx. These results indicate that formation of hot-spots on γ-alumina-supported gold catalysts could be controlled by adding an appropriate dopant. The structure of the catalysts was characterized by techniques such as X-ray powder diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. Addition of a dopant could transfer the active center from Au to AuIII, which resulted in different reaction mechanisms of preferential oxidation of CO in the presence of H2.

Key words: CO oxidation, Dopant, Gold catalyst, Hot-spot

MSC2000: 

  • O643