Chinese Journal of Catalysis ›› 2017, Vol. 38 ›› Issue (3): 529-536.DOI: 10.1016/S1872-2067(17)62750-5

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PtSnNa/SUZ-4: An efficient catalyst for propane dehydrogenation

Hualan Zhoua, Jingjing Gonga, Bolian Xua, Shengcai Denga, Yuanhua Dingb, Lei Yua,b, Yining Fana   

  1. a Key Laboratory of Mesoscopic Chemistry of MOE, Jiangsu Provincial Key Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210046, Jiangsu, China;
    b Jiangsu Key Laboratory of Environmental Material and Environmental Engineering, School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu, China
  • Received:2016-11-16 Revised:2016-12-17 Online:2017-03-18 Published:2017-03-22
  • Supported by:

    This work was supported by the Jiangsu Planned Projects for Postdoctoral Research Funds (1301080C), NNSFC (21202141, 21173182), Key Science & Technology Specific Projects of Yangzhou (YZ20122029), the Innovation Foundation of Yangzhou University (2015CXJ009).

Abstract:

The structure and catalytic properties of PtSn catalysts supported on SUZ-4 and ZSM-5 zeolite have been studied by using various experimental techniques including XRD, nitrogen adsorption, NH3-TPD, TG, H2-TPR and TPO techniques combined with propane dehydrogenation tests. It has been shown that SUZ-4-supported PtSnNa (PtSnNa/SUZ-4) was determined to be a better catalyst for propane dehydrogenation than conventional catalysts supported on ZSM-5, owing to its higher catalytic activity and stability. Dibenzothiophene poisoning experiments were performed to investigate the detailed structures of the two supported catalysts. The characterization of the two catalysts indicates that the distribution of Pt on the porous support affects the activity. In contrast to ZSM-5-supported catalysts, Pt particles on the PtSnNa/SUZ-4 are primarily dispersed over the external surface and are not as readily deactivated by carbon deposition. This is because that the strong acid sites of the SUZ-4 zeolite evidently prevented the impregnation of the Pt precursor H2PtCl6 into the zeolite. In contrast, the weak acid sites of the ZSM-5 zeolite led to more of the precursor entering the zeolite tunnels, followed by transformation to highly dispersed Pt clusters during calcination. In the case of the PtSnNa/ZSM-5, the interactions between Sn oxides and the support were lessened, owing to the weaker acidity of the ZSM-5 zeolite. The dispersed Sn oxides were therefore easier to reduce to the metallic state, thus decreasing the catalytic activity for hydrocarbon dehydrogenation.

Key words: SUZ-4 zeolite, PtSnNa catalyst, Propane dehydrogenation, Catalyst stability, Pt distribution