Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (04): 928-934.doi: 10.3866/PKU.WHXB201202073

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effects of Mg Addition on Catalytic Performance of PtNa/Sn-ZSM-5 in Propane Dehydrogenation

XUE Meng-Wei1,2, ZHOU Yu-Ming1, ZHANG Yi-Wei1, HUANG Li1, LIU Xuan1, DUAN Yong-Zheng1   

  1. 1. School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, P. R. China;
    2. School of Biochemical and Environmental Engineering, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China
  • Received:2011-11-25 Revised:2012-01-27 Published:2012-03-21
  • Contact: ZHOU Yu-Ming
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (50873026, 21106017), Production and Research Prospective Joint Research Project of Jiangsu Province, China (BY2009153), and Specialized Research Fund for the Doctoral Program of Higher Education, China (20100092120047).

Abstract: The effects of Mg addition on the catalytic performance of PtNa/Sn-ZSM-5 in propane dehydrogenation was investigated using catalytic reaction performance tests and physicochemical characterizations such as X-ray diffraction (XRD), nitrogen adsorption, transmission electron microscopy (TEM), NH3 temperature-programmed desorption (NH3-TPD), H2 temperature-programmed reduction (H2-TPR), and O2 temperature-programmed oxidation (O2-TPO). It was found that addition of appropriate amounts of Mg (0.3% and 0.5%, mass fraction) promoted the dispersion of metallic particles and decreased carbon deposition. In these cases, the presence of Mg in the PtMgNa/Sn-ZSM-5 catalyst could inhibit reduction of Sn species, thus more Sn could exist in oxidized states, which is advantageous to the reaction. However, when the content of Mg was excessive, the metallic particles were not well distributed and the particles agglomerated more easily. Moreover, the reduction of Sn species at high temperatures is relatively easy, which is disadvantageous to the reaction. In our experiments, the addition of 0.5% Mg to the PtNa/Sn-ZSM-5 catalyst gave the best catalytic performance. After reaction for 7 h, higher than 95% selectivity toward propene was achieved with a corresponding propane conversion value of 38.7%.

Key words: Mg, Sn-ZSM-5, Propane dehydrogenation, Catalytic performance, Catalyst