高等学校化学学报

高等学校化学学报 ›› 2013, Vol. 34 ›› Issue (5): 1187.doi: 10.7503/cjcu20120983

• 物理化学 • 上一篇    下一篇

xAu/α-MnO2催化剂的结构及催化氧化VOCs气体性能

叶青, 霍飞飞, 王海平, 王娟, 王道   

  1. 北京工业大学环境与能源工程学院, 北京 100124
  • 收稿日期:2012-10-30 出版日期:2013-05-10 发布日期:2013-05-10
  • 通讯作者: 叶 青, 女, 博士, 教授, 主要从事大气污染控制方面的研究. E-mail: yeqing@bjut.edu.cn E-mail:yeqing@bjut.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 20777005)和北京市自然科学基金(批准号: 8082008)资助.

xAu/α-MnO2 Catalysts: Structure and Catalytic Oxidation of Benzene and Toluene

YE Qing, HUO Fei-Fei, WANG Hai-Ping, WANG Juan, WANG Dao   

  1. College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China
  • Received:2012-10-30 Online:2013-05-10 Published:2013-05-10
  • Contact: Qing QingYe E-mail:yeqing@bjut.edu.cn

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摘要：

以NaOH为沉淀剂, 采用沉积-沉淀法制备了α-MnO2负载Au催化剂xAu/α-MnO2(x=1.0%～7.0%, 质量分数), 利用X射线衍射(XRD)、 N2吸附-脱附、 H2程序升温还原(H2-TPR)、 透射电子显微镜(TEM)和X射线光电子能谱(XPS)等技术对所得样品进行了表征, 并对其催化氧化挥发性有机化合物(VOCs, 苯和甲苯)的性能进行了研究. XRD结果表明, 负载Au对α-MnO2载体结构影响不大, 但对其晶粒大小和比表面积略有影响. 随着Au含量的增加, α-MnO2结晶度增强, 颗粒增大, Au粒径明显增大. XPS结果表明, 随着Au负载量的增加, xAu/α-MnO2的晶格氧(O2-), Mn4+和Au3+的浓度增加. H2-TPR结果表明, 由于贵金属的溢氢作用, Au明显提升了xAu/α-MnO2的还原能力, 其中3%Au/α-MnO2的还原能力最强. 负载Au明显影响xAu/α-MnO2的催化性能, xAu/α-MnO2 的催化性能与Au的颗粒分散性、 低温还原性能及表面氧物种密切相关, 其中3%Au/α-MnO2 显示出最佳活性, 其催化氧化苯和甲苯的T100分别为280和250 ℃.

关键词: Au/α-MnO2催化剂, 还原性能, 协同作用, 苯, 甲苯, 催化氧化

Abstract:

α-MnO2-supported gold catalysts(xAu/α-MnO2, x=1.0%—7.0%, mass fraction) were prepared by deposition-precipitation method using NaOH as precipitation agent and characterized by X-ray diffraction(XRD), N2 adsorption-desorption measurement, H2 temperature-programmed reduction(TPR), Transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). Catalytic activities of the materials were evaluated for the oxidation of benzene and toluene. The sizes of Au particle and α-MnO2 support were related with the Au loading over xAu/α-MnO2 samples and increased with Au loading. The result of XPS showed that the molar ratios of O2-/O2-, Mn4+/Mn3+ and Au3+/Au0 increase with adding of Au. It was shown that the loading of gold on α-MnO2 could significantly modify the catalytic activities. The catalytic performance of xAu/α-MnO2 strongly depended upon the Au loading, among which 3% Au/α-MnO2 performed the best activity, T100=280, 250 ℃ for the catalytic oxidation of benzene and toluene, respectively. The excellent performance of 3% Au/α-MnO2 was associated with the highly dispersed Au, good low-temperature reducibility, and synergism at the interface of Au and MnO2 nanodomains.

Key words: Au/α-MnO2 catalyst, Reducibility, Synergism, Benzene, Toluene, Catalytic oxidation

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