Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (10): 2239-2244.doi: 10.3866/PKU.WHXB201308151

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

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

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