Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (2): 344-352.doi: 10.3866/PKU.WHXB201412163

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Modulation of the Acidity and Catalytic Conversion Properties of Y Zeolites Modified by Cerium Cations

ZHANG Chang1, QIN Yu-Cai1, GAO Xiong-Hou2, ZHANG Hai-Tao2, MO Zhou-Sheng3, CHU Chun-Yu1, ZHANG Xiao-Tong1, SONG Li-Juan1,3   

  1. 1. Key Laboratory of Petrochemical Catalytic Science and Technology of Liaoning Province, Liaoning ShiHua University, Fushun 113001, Liaoning Province, P. R. China;
    2. Lanzhou Petrochemical Research Center, Petrochemical Research Institute, Petro China Company Limited, Lanzhou 730060, P. R.China;
    3. College of Chemistry and Chemical Engineering, China University of Petroleum East China, Qingdao 266555, Shandong Province, P. R. China
  • Received:2014-10-08 Revised:2014-12-15 Published:2015-01-26
  • Contact: SONG Li-Juan, GAO Xiong-Hou E-mail:lsong56@263.net;gaoxionghou@petrochina.com.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21076100, 21376114) and Major Program of Petroleum Refining of Catalyst of Petro China Company Limited, China (10-01A-01-01-01).

Abstract:

Y-type zeolites with different cerium ion content were prepared by liquid phase ion exchange (LPIE) and their structural properties were characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), N2 adsorption isotherm, and temperature-programmed desorption of ammonia (NH3-TPD). The influence of cerium ion modification of the Y-type zeolites on the acidity and catalytic behavior was studied by in situ Fourier transform infrared spectroscopy (in situ FTIR) techniques with pyridine and thiophene as probe molecules. The results indicate that the original crystal structures of the zeolites remain unchanged after modification with cerium ions. During the modification process the Ce species tend to be located in sodalite (SOD) cages after calcination and remain in the supercages upon a gradual increase in Ce cation content. The amount and strength of the Brönsted (B) acid sites in the zeolites generated by the modification increases initially and then stabilizes with an increase in Ce ion content. The strong and weak Lewis (L) acid sites related to the non-framework aluminum and the rare earth species increase continuously during the modification process. Thiophene adsorption FTIR spectra indicate that the adsorbed thiophene molecules protonate at the strong Brönsted acid sites of the zeolites. The protonated products then oligomerize. The synergy between Ce species and B acid sites is favorable for the thiophene oligomerization reaction.

Key words: In situ Fourier transform Infrared spectroscopy, CeY, Acidity, Thiophene, Catalytic conversion

MSC2000: 

  • O643