物理化学学报 >> 2011, Vol. 27 >> Issue (12): 2872-2880.doi: 10.3866/PKU.WHXB20112872

催化和表面科学 上一篇    下一篇

α-MnO2负载纳米Au催化剂低温催化氧化CO和苯的性能

叶青, 霍飞飞, 闫立娜, 王娟, 程水源, 康天放   

  1. 北京工业大学环境与能源工程学院, 北京 100124
  • 收稿日期:2011-06-13 修回日期:2011-09-13 发布日期:2011-11-25
  • 通讯作者: 叶青 E-mail:yeqing@bjut.edu.cn
  • 基金资助:

    国家自然科学基金(20777005), 北京市自然科学基金(8082008)和北京市组织部优秀人才基金(20071D0501500210)资助项目

Highly Active Au/α-MnO2 Catalysts for the Low-Temperature Oxidation of Carbon Monoxide and Benzene

YE Qing, HUO Fei-Fei, YAN Li-Na, WANG Juan, CHENG Shui-Yuan, KANG Tian-Fang   

  1. College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, P. P. China
  • Received:2011-06-13 Revised:2011-09-13 Published:2011-11-25
  • Contact: YE Qing E-mail:yeqing@bjut.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20777005), Natural Science Foundation of Beijing, China (8082008) and Beijing Municipal Foundation for Excellent Person of Ability, China (20071D0501500210).

摘要: 以尿素为沉淀剂用沉积-沉淀法制备了α-MnO2负载Au 催化剂xAu/α-MnO2 (x=0-7(对应的Au 负载量(质量分数)分别为0-7%)), 使用X 射线粉末衍射(XRD)、N2-吸附/脱附、透射电镜(TEM)、X 射线光电子能谱(XPS)和H2-程序升温还原(H2-TPR)等技术对所制样品进行了表征, 并测定其对CO和苯的催化氧化性能. XRD结果表明, 负载Au对α-MnO2载体结构影响不大, 随Au含量的增加, Au颗粒明显增大. N2-吸附/脱附和TEM结果表明, Au的加入对xAu/α-MnO2的比表面积、孔容和孔径等结构性能影响较小, 表明Au分布在α-MnO2载体表面, 未阻塞其孔道. XPS结果表明, 随着Au负载量的增加, xAu/α-MnO2中的O2-/(O22- 或O-)、Mn4+/Mn3+和Au3+/Au0的摩尔比在增加, 表明其晶格氧、Mn4+和Au3+的浓度在增加. 由于贵金属的溢氢作用, Au 明显促进xAu/α-MnO2氧化还原能力, 其中3Au/α-MnO2具有最高的氧化还原性. 负载Au明显影响xAu/α-MnO2样品的催化活性, xAu/α-MnO2的催化性能与Au 的分散性、氧化还原性能及表面氧物种的种类密切相关, 其中3Au/α-MnO2显示出最佳活性, 其催化氧化CO的T90=80 °C, 苯的T90=200 °C.

关键词: &, alpha, -MnO2负载Au催化剂, 低温还原性, 相互作用, CO氧化, 苯催化燃烧

Abstract: α-MnO2-supported gold catalysts (xAu/α-MnO2, x=0-7 (corresponding to the Au loading (mass fraction) of 0-7%) were prepared by a deposition- precipitation method using urea as a precipitation agent and characterized by different techniques such as X-ray diffraction (XRD), N2 adsorption-desorption measurements, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (TPR). The catalytic activities of the materials were evaluated for the oxidation of CO and benzene. The Au particle size was found to be related to the Au loading of the xAu/ α-MnO2 samples and increased with Au loading. XPS results showed that the mole ratios of O2-/(O22- or O-), Mn4+/Mn3+ and Au3+/Au0 increased upon the addition of Au. The loading of gold over α-MnO2 significantly modified the catalytic activities. The catalytic performance of xAu/α-MnO2 strongly depended on the Au loading, and 3Au/α-MnO2 gained the best activity at T90=80 °C and T90=20 °C for the catalytic oxidation of CO and benzene, respectively. The excellent performance of 3Au/α-MnO2 is associated with highly dispersed Au, good low-temperature reducibility, and a synergism at the interface between theAu and MnO2 nanodomains.

Key words: &, alpha, -MnO2 supported gold catalyst, Low-temperature reducibility, Synergistic action, Carbon monoxide oxidation, Benzene combustion

MSC2000: 

  • O643