Acta Phys. -Chim. Sin. ›› 1995, Vol. 11 ›› Issue (11): 974-978.doi: 10.3866/PKU.WHXB19951104

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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
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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