物理化学学报 >> 1995, Vol. 11 >> Issue (11): 974-978.doi: 10.3866/PKU.WHXB19951104

研究论文 上一篇    下一篇

Cu-ZSM-5分子筛上[Cu-O-Cu]2+物种的原位红外光谱研究

王必勋,伏义路,方书农   

  1. 中国科技术大学化学物理系，合肥 230026
  • 收稿日期:1994-12-06 修回日期:1995-04-26 发布日期:1995-11-15
  • 通讯作者: 伏义路

A Study of [Cu-O-Cu]2+ Species on Cu-ZSM-5 Zeolite by in situ Infrared Spectroscopy

Wang Bi-Xun,Fu Yi-Lu,Fang Shu-Nong   

  1. Department of Chemical Physics, University of Science and Technology of China,Hefei 230026
  • Received:1994-12-06 Revised:1995-04-26 Published:1995-11-15
  • Contact: Fu Yi-Lu

PDF

2850

赞

摘要：

通过原位监测Cu－ZSM－5分子筛的振动红外光谱随温度及不同处理条件的变化情况，观察到［Cu－O－Cu］2＋物种的形成过程，即两个Cu（OH）＋在脱水过程中经二聚形成［Cu－O－Cu］2＋. 低交换度样品开始产生［Cu－O－Cu］2＋物种所需脱水温度较高. 通过观察不同处理条件对［Cu－O－Cu］2＋的影响，说明Cu2＋是通过脱出［Cu－O－Cu］2＋中的超晶格氧而被还原为Cu＋. 较高温度时［Cu－O－Cu］2＋中的超晶格氧能与气相中的氧达到某种平衡. 超晶格氧的脱出性能是影响Cu－ZSM－5分子筛上铜价态变化的重要因素．

关键词: Cu-ZSM-5分子筛, 原位红外光谱, 超晶格氧, [Cu-O-Cu]2+物种

Abstract:

The appearance of [Cu-O-Cu]2+ species with increasing temperature is observed by in situ infrared spectra. [Cu-O-Cu]2+ is formed by dehydrated dimer composed of two Cu(OH)+. Low copper content sample needs higher temperature to form [Cu-O-Cu]2+ than high copper-conten ones. Cu2+ ions can be reduced to Cu+ by release of oxygen from [Cu-O-Cu]2+. In oxygen atmosphere, an equilibrium can be reached between the oxygen in [Cu-O-Cu]2+ and the oxygen in gas phase at high temperature. The property of extra-lattice oxygen is an important factor in determining the change of copper valence.

Key words: Cu-ZSM-5 zeolite, In-situinfrared spcetra, Extra-lattice oxygen, [Cu-O-Cu]2+ species