催化学报

催化学报 ›› 2011, Vol. 32 ›› Issue (8): 1364-1369.DOI: 10.3724/SP.J.1088.2011.10324

• 研究论文 • 上一篇    下一篇

助剂形态对 Pt/γ-Al2O3 催化剂抗积炭性能的影响

俞佳枫 1,3, 方雯 1,3, 葛庆杰 1,a, 徐恒泳 1,2,b   

  1. 1 中国科学院大连化学物理研究所, 辽宁大连 116023; 2 中国科学院大连化学物理研究所催化基础国家重点实验室, 辽宁大连 116023; 3 中国科学院研究生院, 北京 100049
  • 收稿日期:2011-03-24 修回日期:2011-04-01 出版日期:2011-08-05 发布日期:2014-12-26

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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摘要： 采用 CO 和 H2 脉冲吸附、程序升温还原、NH3 程序升温脱附及 X 射线衍射等手段对各金属氧化物改性的 Pt/Al2O3 催化剂进行了表征, 研究了助剂形态对 Pt/Al2O3 催化剂在非临氢条件下催化环己烷脱氢反应性能的影响. 结果表明, 催化剂稳定性从高到低依次为 Zr-Pt/Al2O3 > Ca-Pt/Al2O3 > Ce-Pt/Al2O3 > Zn-Pt/Al2O3 > Ba-Pt/Al2O3. 加入的助剂通过增加 Pt 分散度和促进氢溢流来增加催化剂的抗积炭性能, 因此助剂需具有较高的热稳定性和化学稳定性, 在催化剂的焙烧过程中以氧化物形态均匀分散在载体表面, 不能过度聚集、或与载体反应生成铝酸盐、或与活性金属反应形成合金. Ca 和 La 同时改性的催化剂性能不如单一助剂, 因为助剂间相互作用导致催化剂酸中心增强, 溢流氢能力减弱.

关键词: 金属氧化物, 铂, 氧化铝, 环己烷脱氢, 抗积炭

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