Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (7): 1483-1491.doi: 10.3866/PKU.WHXB201704133

• ARTICLE • Previous Articles     Next Articles

Effect of Hydrogen pre-treatment on the catalytic properties of Zn/HZSM-5 zeolite for ethylene aromatization reaction

Chun-Lei WEI1,2,Jie GAO1,2,Kai WANG1,2,Mei DONG1,*(),Wei-Bin FAN1,*(),Zhang-Feng QIN1,Jian-Guo WANG1   

  1. 1 State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, P. R. China
    2 University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2017-02-16 Published:2017-05-31
  • Contact: Mei DONG,Wei-Bin FAN E-mail:mdong@sxicc.ac.cn;fanwb@sxicc.ac.cn
  • Supported by:
    the National Natural Science Foundation of China(21273264);the National Natural Science Foundation of China(21273263);Major State Basic Research Development Program of China(973)(2011CB201403);Natural Science Foundation of Shanxi Province, China(2012011005-2)

Abstract:

After hydrogen pre-treatment at different temperatures, the textural and physicochemical properties of Zn/HZSM-5 were studied by X-ray diffraction (XRD), N2 adsorption-desorption, Fourier transform infrared (FT-IR) spectroscopy, temperature programmed desorption of NH3 (NH3-TPD), and X-ray photoelectron spectroscopy (XPS) techniques. The results showed that the temperatures for hydrogen pretreatment of Zn/HZSM-5 exerted a significant influence on both the contents and state of zinc species. The pre-treatment with hydrogen at temperature higher than 600℃ resulted in a significant leaching of zinc species from the catalysts, which occurred due to the reduction and sublimation of zinc species. The XPS characterization revealed that the hydrogen pre-treatment at different temperatures causes the redistribution of ZnOH+ and ZnO species in the zeolite. A linear correlation between the amount of ZnOH+ species and the selectivity to aromatics over the Zn/HZSM-5 catalysts pretreated with hydrogen at different temperatures was observed, suggesting that ZnOH+ species may promote the formation of aromatics in ethylene aromatization reaction.

Key words: Molecular sieves, Ethylene aromatization, Hydrogen pretreatment, Zn species

MSC2000: 

  • O643