催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (3): 234-238.

• 研究论文 • 上一篇    下一篇

Pd/ZnO催化剂的还原及其催化甲醇水蒸气重整制氢

王艳华1,张敬畅2,徐恒泳3,白雪峰1   

  1. 1 黑龙江省石油化学研究院, 黑龙江哈尔滨 150040; 2 北京化工大学现代催化研究所, 北京 100029; 3 中国科学院大连化学物理研究所, 辽宁大连 116023
  • 收稿日期:2007-03-25 出版日期:2007-03-25 发布日期:2007-03-25

Reduction of Pd/ZnO Catalyst and Its Catalytic Activity for Steam Reforming of Methanol

WANG Yanhua1*, ZHANG Jingchang2, XU Hengyong3, Bai Xuefeng1   

  1. 1 Heilongjiang Institute of Petrochemistry, Harbin 150040, Heilongjiang, China; 2 Institute of Modern Catalysis, Beijing University of Chemical Technology, Beijing 100029, China; 3 Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2007-03-25 Online:2007-03-25 Published:2007-03-25

PDF

1026

被引次数

80

摘要： 考察了共沉淀法制备的15.9%Pd/ZnO催化剂的还原对甲醇水蒸气重整制氢反应的影响. 结果显示,当催化剂的还原温度为523～573 K时, 523 K下反应的甲醇转化率达到了41.6%, CO2选择性为94.6%, 出口CO浓度为1.26%. X射线衍射结果显示,当催化剂的还原温度为523 K时PdZn合金开始形成. 还原温度为523～573 K范围内催化剂活性的提高归因于 5～14 nm PdZn合金粒子的存在. 用程序升温还原及X射线衍射表征手段探究了还原过程中Pd与ZnO之间的相互作用. 结果表明, Pd/ZnO可能经历了PdO/ZnO→Pd/ZnO→PdZnO1-x/ZnO→PdZn合金/ZnO的还原过程,而部分PdZn合金在反应过程中可重新被氧化成PdZnO1-x. 对反应的活性物种进行了初步探讨.

关键词: 钯, 氧化锌, 负载型催化剂, 甲醇水蒸气重整, 钯锌合金, 活性物种, 还原

Abstract: The effect of reduction temperature of the coprecipitated 15.9%Pd/ZnO catalyst on the catalytic activity for steam reforming of methanol was investigated. The results showed that methanol conversion at 523 K reached a maximum of 41.6% with a CO2 selectivity of 94.6% and an outlet CO concentration of 1.26% over the catalyst reduced at 523-573 K. X-ray diffraction analysis revealed that a PdZn alloy began to form at a reduction temperature of 523 K. The improvement in activity at reduction temperature ranging from 523 to 573 K was attributed to the formation of the PdZn alloy with crystal size of 5-14 nm. The interaction between Pd and ZnO upon reduction was also explored by means of temperature-programmed reduction and X-ray diffraction. The results demonstrated that the reduction over Pd/ZnO might undergo a process PdO/ZnO→Pd/ZnO→PdZnO1-x/ZnO→PdZn alloy/ZnO. The PdZn alloy was found to be partially oxidized to PdZnO1-x again during the reaction. The PdZn alloy and PdZnO1-x species might be the real active species.

Key words: palldium, zinc oxide, supported catalyst, steam reforming of methanol, PdZn alloy, active species, reduction