Chinese Journal of Catalysis

Chinese Journal of Catalysis ›› 2011, Vol. 32 ›› Issue (8): 1364-1369.DOI: 10.3724/SP.J.1088.2011.10324

• Research papers • Previous Articles     Next Articles

Effect of Oxide Phase of Promoters on Coke Resistance over Pt/γ-Al2O3 Catalyst

YU Jiafeng1,3, FANG Wen1,3, GE Qingjie1,a, XU Hengyong1,2,b   

  1. 1Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China; 2State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China; 3Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2011-03-24 Revised:2011-04-01 Online:2011-08-05 Published:2014-12-26

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Abstract: The effects of different promoters on coke deposition over Pt/Al2O3 catalyst for hydrogen-free cyclohexane dehydrogenation were investigated by catalytic tests and a series of analytical techniques such as X-ray diffraction, CO and H2 chemisorption, temperature-programmed desorption of NH3, and temperature-programmed reduction. The stability of different promoters modified catalysts is in the order of Zr-Pt/Al2O3 > Ca-Pt/Al2O3 > Ce-Pt/Al2O3 > Zn-Pt/Al2O3 > Ba-Pt/Al2O3. The results clearly show that the addition of promoters to the Pt/Al2O3 catalyst could inhibit coke deposition by increasing Pt dispersion and promoting hydrogen spillover. That is attributed to the high thermodynamic and chemical stability of the metal oxide promoters. They must be highly dispersed and stable without reacting with Al2O3 in calcination or forming alloy with Pt in reduction. The catalytic property of CaLa-Pt/Al2O3 is worse than either Ca-Pt/Al2O3 or La-Pt/Al2O3 because the acidity of catalyst is enhanced and the spillover hydrogen is reduced due to Ca-La strong interaction.

Key words: metal oxide, platinum, alumina, cyclohexane dehydrogenation, coke resistance