物理化学学报 >> 2013, Vol. 29 >> Issue (10): 2239-2244.doi: 10.3866/PKU.WHXB201308151

催化和表面科学 上一篇    下一篇

Fe3O4修饰的Pt-Ru/C纳米催化剂的制备及其在无溶剂条件下邻氯硝基苯选择性加氢的催化性能

王亚南1,2, 杨玉霞1, 李永文1, 赖俊华2,3, 孙鲲鹏1   

  1. 1 中国科学院兰州化学物理研究所绿色化学与催化中心, 兰州 730000;
    2 中国科学院大学, 北京 100049;
    3 中国科学院寒区旱区环境与工程研究所, 兰州 730000
  • 收稿日期:2013-04-10 修回日期:2013-08-15 发布日期:2013-09-26
  • 通讯作者: 孙鲲鹏 E-mail:sunkp@lzb.ac.cn

Preparation of Fe3O4 Modified Pt-Ru/C Nanocatalysts and Their Catalytic Properties for the Selective Hydrogenation of ortho-Chloronitrobenzene under Solvent-Free Conditions

WANG Ya-Nan1,2, YANG Yu-Xia1, LI Yong-Wen1, LAI Jun-Hua2,3, SUN Kun-Peng1   

  1. 1 Centre for Green Chemistry and Catalysis, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China;
    2 University of Chinese Academy of Sciences, Beijing 100049, P. R. China;
    3 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
  • Received:2013-04-10 Revised:2013-08-15 Published:2013-09-26
  • Contact: SUN Kun-Peng E-mail:sunkp@lzb.ac.cn

摘要:

采用浸渍法制备了一系列Pt/Ru质量比不同的Fe3O4修饰的Pt-Ru/Fe3O4/C催化剂, 运用透射电镜(TEM)、能量弥散X射线谱(EDX)、X射线光电子能谱(XPS)、X射线粉末衍射(XRD)等手段对Pt-Ru/Fe3O4/C一系列催化剂进行了表征, 并考察了Pt/Ru质量比不同对催化剂Pt-Ru/Fe3O4/C在无溶剂条件下催化邻氯硝基苯(o-CNB)选择性加氢制备邻氯苯胺(o-CAN)催化性能的影响. 研究结果表明, 催化剂的催化活性和对目标产物的选择性跟活性组分Pt、Ru比例有关. 随着Pt/Ru比例的减小, 目标产物o-CAN的选择性有所升高, 然而反应物o-CNB的转化率有所下降. 当Pt/Ru的质量比为2时, o-CNB的转化率降为76.5%, 而目标产物o-CAN的选择性仍然为100%. 与此同时, 我们还对Pt-Ru/Fe3O4/C催化剂高的催化活性和目标产物的高选择性可能的原因进行了分析.

关键词: 选择性加氢, 无溶剂, 氯代硝基苯, 氯代苯胺, 四氧化三铁, 铂,

Abstract:

Aseries of Fe3O4-modified Pt-Ru/C nanocomposite catalysts were prepared by impregnation and hydrazine hydrate reduction of Pt and Ru precursors. Various Pt/Ru mass ratios of the catalysts were examined in terms of catalytic activity. They were characterized by transmission electron microscopic measurements (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The average diameters of the catalysts with different mass ratios of Pt/Ru were in a range of 2.2-2.5 nmwith narrowsize distributions. The valence states of the nanoparticles indicate strong interactions between the Pt and the carbon support or with Fe3O4. The XRDpatterns of the 8Pt-1Ru/Fe3O4/C, 6Pt-1Ru/Fe3O4/ C, 4Pt-1Ru/Fe3O4/C, and 2Pt-1Ru/Fe3O4/Ccatalysts have similar profiles, which are attributed to the cubic phase of pure Fe3O4 (i.e., no Pt or Ru present). These catalysts selectively hydrogenate ortho-chloronitrobenzene (o-CNB) to the corresponding ortho-chloroaniline (o-CAN) under solvent-free conditions that not only allowed high substrate concentrations promoting the hydrogenation reaction, but also enabled easy product separation and purification. They exhibited excellent catalytic activity (turnover frequency (TOF) range: 0.98-2.09 mol·mol-1·s-1) and up to 100% o-CAN selectivity, which was composition-dependent. The o-CAN yield selectivity monotonically increased with the proportion of Ru; however, the catalytic activity decreased. The high catalytic activity and selectivity of Pt-Ru/Fe3O4/Cnanoparticles are attributed to electron transfer between the two metals and Fe3O4.

Key words: Selective hydrogenation, Solvent-free, Chloronitrobenzene, Chloroaniline, Ferroferric oxide, Platinum, Ruthenium

MSC2000: 

  • O643