物理化学学报 >> 2002, Vol. 18 >> Issue (01): 82-86.doi: 10.3866/PKU.WHXB20020119

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Cu-Ni/Zn催化剂甲醇裂解机理原位XPS研究

席靖宇;王志飞;王卫平;吕功煊   

  1. 中国科学院兰州化学物理研究所　羰基合成与选择氧化国家重点实验室,兰州 　730000
  • 收稿日期:2001-06-23 修回日期:2001-09-18 发布日期:2002-01-15
  • 通讯作者: 吕功煊 E-mail:gxlu@ns.azb.ac.cn

In-situ XPS Study for Reaction Mechanism of Methanol Decomposition over Cu-Ni/Zn Catalyst

Xi Jing-Yu;Wang Zhi-Fei;Wang Wei-Ping;Lü Gong-Xuan   

  1. State Key Laboratory for Oxo Synthesis and Selective Oxidation,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou　730000
  • Received:2001-06-23 Revised:2001-09-18 Published:2002-01-15
  • Contact: Lü Gong-Xuan E-mail:gxlu@ns.azb.ac.cn

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摘要： 利用原位XPS 和TPDMS 技术研究了CuNi/Zn催化剂在甲醇裂解反应中的机理和活性中心.TPDMS脱附产物中仅检测到CH3OH、H2和CO,而未发现CH4和CH3OCH3、HCOOCH3等其它含氧物种,说明在CH3OH裂解过程中仅包括O－H、C－H键的断裂,而不存在C－O键的断裂过程.Insitu XPS的研究发现,在反应温度升高到200 ℃以上时,Cu/Zn催化剂中的Zn明显被还原,反映出Cu/Zn催化剂失活过程的CuZn合金生成过程,而在CuNi/Zn催化剂中未观察到Zn的还原,且表面出现Cu＋/Cu0共存的现象.Cu＋和Cu0很可能共同构成催化剂表面的活性中心,Cu＋应该是在甲醇裂解反应过程中形成的中间态.产物氢从CuNi/Zn 催化剂表面脱附为反应的控速步骤.

关键词: 甲醇裂解, 氢气, Cu-Ni/Zn催化剂, 原位-XPS, 反应机理, 活性中心

Abstract: Insitu XPS and TPDMS techniques were used to study the reaction mechanism and the active center of CuNi/Zn catalyst for methanol decomposition.Significant amount of CH3OH、H2 and CO were detected during the methanol decomposition with TPDMS,however no evidences of CH4、CH3OCH3 and HCOOCH3 formation were obtained.TPDMS results indicated that O－H and C－H bonds instead of C－O bond were broken in methanol decomposition on Cu/Zn/Ni catalyst.It was found that H2 desorption from the surface of CuNi/Zn catalyst was the rate control step.Insitu XPS studies confirmed that the Zn species was easily reduced when temperature was higher than 200 ℃ in Cu/Zn catalyst.However,similar reduction of Zn was not observed in Cu/Zn/Ni catalyst.Furthermore,both Cu＋ and Cu0 species were observed in Cu/Zn/Ni catalyst.Our study indicated that active center(s) in Cu/Zn/Ni catalyst may be Cu0 and/or Cu＋ species,in which Cu＋ formed during the reaction.

Key words: Methanol decomposition, Hydrogen, Cu-Ni/Zn catalyst, In-situ XPS